Stirling type formula for Sum on $ln(n)^2$
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Is there a similar formula like the Stirling one on the sum over $ln(n)$ (take logarithms on its factorial representation):
$$sum_n=1^N ln(n) = N ln(N)-N+ln(N)/2+ln(2pi)/2+mathcalO(ln(N)/N)$$
but on the sum over its squares?
$$sum_n=1^N (ln(n))^2$$
I already advanced on getting good approximation on asymptotics integrating $ln(n)^2$ and arrive to correct terms till $mathcalO(N)$ order. But further advance is becoming hard for me in $mathcalO(ln(N))$ terms.
I am specially interested in $mathcalO(1)$ term.
sequences-and-series logarithms asymptotics
 |Â
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up vote
2
down vote
favorite
Is there a similar formula like the Stirling one on the sum over $ln(n)$ (take logarithms on its factorial representation):
$$sum_n=1^N ln(n) = N ln(N)-N+ln(N)/2+ln(2pi)/2+mathcalO(ln(N)/N)$$
but on the sum over its squares?
$$sum_n=1^N (ln(n))^2$$
I already advanced on getting good approximation on asymptotics integrating $ln(n)^2$ and arrive to correct terms till $mathcalO(N)$ order. But further advance is becoming hard for me in $mathcalO(ln(N))$ terms.
I am specially interested in $mathcalO(1)$ term.
sequences-and-series logarithms asymptotics
1
Have you tried the Euler-Maclaurin formula?
â Lord Shark the Unknown
Aug 27 at 16:24
Maple says it's $$(ln(N)^2 - 2 ln(N)+2)N + fracln(N)^22 -frac ln left( 2,pi right)^22-fracpi^224 +fracgamma^22+gamma left( 1 right) + ldots $$
â Robert Israel
Aug 27 at 16:38
Sorry Robert, not sure what $$gamma(1)$$ means
â 24th_moonshine
Aug 27 at 16:46
Thanks @LordSharktheUnknown to your suggestion I could arrive to the O(ln(N)^2) term. But still no clear idea on how to get constant term. I saw some proof of Stirling constant term but no general method to apply here. Any idea on that?
â 24th_moonshine
Aug 27 at 16:48
1
$$sum _n=1^N log ^2(n)=sum _n=1^N left(undersetxto 0textlimfracpartial ^2n^xpartial x^2right)=undersetxto 0textlimfracpartial ^2partial x^2left(sum _n=1^N n^xright)=undersetxto 0textlimfracpartial ^2H_N^(-x)partial x^2=undersetxto 0textlim(textHarmonicNumber^(0,2)(N,-x))=fracgamma ^22-fracpi ^224-frac12 log ^2(2 pi )+gamma _1-zeta ^(2,0)(0,1+N)$$
â Mariusz Iwaniuk
Aug 29 at 14:33
 |Â
show 3 more comments
up vote
2
down vote
favorite
up vote
2
down vote
favorite
Is there a similar formula like the Stirling one on the sum over $ln(n)$ (take logarithms on its factorial representation):
$$sum_n=1^N ln(n) = N ln(N)-N+ln(N)/2+ln(2pi)/2+mathcalO(ln(N)/N)$$
but on the sum over its squares?
$$sum_n=1^N (ln(n))^2$$
I already advanced on getting good approximation on asymptotics integrating $ln(n)^2$ and arrive to correct terms till $mathcalO(N)$ order. But further advance is becoming hard for me in $mathcalO(ln(N))$ terms.
I am specially interested in $mathcalO(1)$ term.
sequences-and-series logarithms asymptotics
Is there a similar formula like the Stirling one on the sum over $ln(n)$ (take logarithms on its factorial representation):
$$sum_n=1^N ln(n) = N ln(N)-N+ln(N)/2+ln(2pi)/2+mathcalO(ln(N)/N)$$
but on the sum over its squares?
$$sum_n=1^N (ln(n))^2$$
I already advanced on getting good approximation on asymptotics integrating $ln(n)^2$ and arrive to correct terms till $mathcalO(N)$ order. But further advance is becoming hard for me in $mathcalO(ln(N))$ terms.
I am specially interested in $mathcalO(1)$ term.
sequences-and-series logarithms asymptotics
edited Aug 27 at 17:34
ComplexYetTrivial
3,047626
3,047626
asked Aug 27 at 16:23
24th_moonshine
865
865
1
Have you tried the Euler-Maclaurin formula?
â Lord Shark the Unknown
Aug 27 at 16:24
Maple says it's $$(ln(N)^2 - 2 ln(N)+2)N + fracln(N)^22 -frac ln left( 2,pi right)^22-fracpi^224 +fracgamma^22+gamma left( 1 right) + ldots $$
â Robert Israel
Aug 27 at 16:38
Sorry Robert, not sure what $$gamma(1)$$ means
â 24th_moonshine
Aug 27 at 16:46
Thanks @LordSharktheUnknown to your suggestion I could arrive to the O(ln(N)^2) term. But still no clear idea on how to get constant term. I saw some proof of Stirling constant term but no general method to apply here. Any idea on that?
â 24th_moonshine
Aug 27 at 16:48
1
$$sum _n=1^N log ^2(n)=sum _n=1^N left(undersetxto 0textlimfracpartial ^2n^xpartial x^2right)=undersetxto 0textlimfracpartial ^2partial x^2left(sum _n=1^N n^xright)=undersetxto 0textlimfracpartial ^2H_N^(-x)partial x^2=undersetxto 0textlim(textHarmonicNumber^(0,2)(N,-x))=fracgamma ^22-fracpi ^224-frac12 log ^2(2 pi )+gamma _1-zeta ^(2,0)(0,1+N)$$
â Mariusz Iwaniuk
Aug 29 at 14:33
 |Â
show 3 more comments
1
Have you tried the Euler-Maclaurin formula?
â Lord Shark the Unknown
Aug 27 at 16:24
Maple says it's $$(ln(N)^2 - 2 ln(N)+2)N + fracln(N)^22 -frac ln left( 2,pi right)^22-fracpi^224 +fracgamma^22+gamma left( 1 right) + ldots $$
â Robert Israel
Aug 27 at 16:38
Sorry Robert, not sure what $$gamma(1)$$ means
â 24th_moonshine
Aug 27 at 16:46
Thanks @LordSharktheUnknown to your suggestion I could arrive to the O(ln(N)^2) term. But still no clear idea on how to get constant term. I saw some proof of Stirling constant term but no general method to apply here. Any idea on that?
â 24th_moonshine
Aug 27 at 16:48
1
$$sum _n=1^N log ^2(n)=sum _n=1^N left(undersetxto 0textlimfracpartial ^2n^xpartial x^2right)=undersetxto 0textlimfracpartial ^2partial x^2left(sum _n=1^N n^xright)=undersetxto 0textlimfracpartial ^2H_N^(-x)partial x^2=undersetxto 0textlim(textHarmonicNumber^(0,2)(N,-x))=fracgamma ^22-fracpi ^224-frac12 log ^2(2 pi )+gamma _1-zeta ^(2,0)(0,1+N)$$
â Mariusz Iwaniuk
Aug 29 at 14:33
1
1
Have you tried the Euler-Maclaurin formula?
â Lord Shark the Unknown
Aug 27 at 16:24
Have you tried the Euler-Maclaurin formula?
â Lord Shark the Unknown
Aug 27 at 16:24
Maple says it's $$(ln(N)^2 - 2 ln(N)+2)N + fracln(N)^22 -frac ln left( 2,pi right)^22-fracpi^224 +fracgamma^22+gamma left( 1 right) + ldots $$
â Robert Israel
Aug 27 at 16:38
Maple says it's $$(ln(N)^2 - 2 ln(N)+2)N + fracln(N)^22 -frac ln left( 2,pi right)^22-fracpi^224 +fracgamma^22+gamma left( 1 right) + ldots $$
â Robert Israel
Aug 27 at 16:38
Sorry Robert, not sure what $$gamma(1)$$ means
â 24th_moonshine
Aug 27 at 16:46
Sorry Robert, not sure what $$gamma(1)$$ means
â 24th_moonshine
Aug 27 at 16:46
Thanks @LordSharktheUnknown to your suggestion I could arrive to the O(ln(N)^2) term. But still no clear idea on how to get constant term. I saw some proof of Stirling constant term but no general method to apply here. Any idea on that?
â 24th_moonshine
Aug 27 at 16:48
Thanks @LordSharktheUnknown to your suggestion I could arrive to the O(ln(N)^2) term. But still no clear idea on how to get constant term. I saw some proof of Stirling constant term but no general method to apply here. Any idea on that?
â 24th_moonshine
Aug 27 at 16:48
1
1
$$sum _n=1^N log ^2(n)=sum _n=1^N left(undersetxto 0textlimfracpartial ^2n^xpartial x^2right)=undersetxto 0textlimfracpartial ^2partial x^2left(sum _n=1^N n^xright)=undersetxto 0textlimfracpartial ^2H_N^(-x)partial x^2=undersetxto 0textlim(textHarmonicNumber^(0,2)(N,-x))=fracgamma ^22-fracpi ^224-frac12 log ^2(2 pi )+gamma _1-zeta ^(2,0)(0,1+N)$$
â Mariusz Iwaniuk
Aug 29 at 14:33
$$sum _n=1^N log ^2(n)=sum _n=1^N left(undersetxto 0textlimfracpartial ^2n^xpartial x^2right)=undersetxto 0textlimfracpartial ^2partial x^2left(sum _n=1^N n^xright)=undersetxto 0textlimfracpartial ^2H_N^(-x)partial x^2=undersetxto 0textlim(textHarmonicNumber^(0,2)(N,-x))=fracgamma ^22-fracpi ^224-frac12 log ^2(2 pi )+gamma _1-zeta ^(2,0)(0,1+N)$$
â Mariusz Iwaniuk
Aug 29 at 14:33
 |Â
show 3 more comments
1 Answer
1
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up vote
0
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I've encountered an exercise recently which gives an asymptotic formula
$$
sum_1^N log^2(n)= left( n +frac 12right)log^2(n) -2n log(n) +2n + C + r_n quad [r_n to 0, C texta constant].
$$
Hope this could help.
The derivation TBA...
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
I've encountered an exercise recently which gives an asymptotic formula
$$
sum_1^N log^2(n)= left( n +frac 12right)log^2(n) -2n log(n) +2n + C + r_n quad [r_n to 0, C texta constant].
$$
Hope this could help.
The derivation TBA...
add a comment |Â
up vote
0
down vote
I've encountered an exercise recently which gives an asymptotic formula
$$
sum_1^N log^2(n)= left( n +frac 12right)log^2(n) -2n log(n) +2n + C + r_n quad [r_n to 0, C texta constant].
$$
Hope this could help.
The derivation TBA...
add a comment |Â
up vote
0
down vote
up vote
0
down vote
I've encountered an exercise recently which gives an asymptotic formula
$$
sum_1^N log^2(n)= left( n +frac 12right)log^2(n) -2n log(n) +2n + C + r_n quad [r_n to 0, C texta constant].
$$
Hope this could help.
The derivation TBA...
I've encountered an exercise recently which gives an asymptotic formula
$$
sum_1^N log^2(n)= left( n +frac 12right)log^2(n) -2n log(n) +2n + C + r_n quad [r_n to 0, C texta constant].
$$
Hope this could help.
The derivation TBA...
answered Aug 27 at 16:42
xbh
3,062219
3,062219
add a comment |Â
add a comment |Â
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1
Have you tried the Euler-Maclaurin formula?
â Lord Shark the Unknown
Aug 27 at 16:24
Maple says it's $$(ln(N)^2 - 2 ln(N)+2)N + fracln(N)^22 -frac ln left( 2,pi right)^22-fracpi^224 +fracgamma^22+gamma left( 1 right) + ldots $$
â Robert Israel
Aug 27 at 16:38
Sorry Robert, not sure what $$gamma(1)$$ means
â 24th_moonshine
Aug 27 at 16:46
Thanks @LordSharktheUnknown to your suggestion I could arrive to the O(ln(N)^2) term. But still no clear idea on how to get constant term. I saw some proof of Stirling constant term but no general method to apply here. Any idea on that?
â 24th_moonshine
Aug 27 at 16:48
1
$$sum _n=1^N log ^2(n)=sum _n=1^N left(undersetxto 0textlimfracpartial ^2n^xpartial x^2right)=undersetxto 0textlimfracpartial ^2partial x^2left(sum _n=1^N n^xright)=undersetxto 0textlimfracpartial ^2H_N^(-x)partial x^2=undersetxto 0textlim(textHarmonicNumber^(0,2)(N,-x))=fracgamma ^22-fracpi ^224-frac12 log ^2(2 pi )+gamma _1-zeta ^(2,0)(0,1+N)$$
â Mariusz Iwaniuk
Aug 29 at 14:33