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Search: a276593 -id:a276593
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Numerator of the rational part of the sum of reciprocals of even powers of odd numbers, i.e., Sum_{k>=1} 1/(2*k-1)^(2*n).
+0
6
1, 1, 1, 17, 31, 691, 5461, 929569, 3202291, 221930581, 4722116521, 56963745931, 14717667114151, 2093660879252671, 86125672563201181, 129848163681107301953, 868320396104950823611, 209390615747646519456961, 14129659550745551130667441, 16103843159579478297227731
OFFSET
1,4
COMMENTS
Apart from signs, same as A089171 and A279370. - Peter Bala, Feb 07 2019
LINKS
Siddharth Dwivedi, Vivek Kumar Singh, and Abhishek Roy, Semiclassical limit of topological Rényi entropy in 3d Chern-Simons theory, arXiv:2007.07033 [hep-th], 2020. See also J. of High Energy Physics (2020) Vol. 2020, Issue 12, Article 132.
FORMULA
a(n)/A276593(n) + A276594(n)/A276595(n) = A046988(n)/A002432(n).
a(n)/A276593(n) = (-1)^(n+1) * B_{2*n} * (2^(2*n) - 1) / (2 * (2*n)!), where B_n is the Bernoulli number. - Seiichi Manyama, Sep 03 2018
MAPLE
seq(numer(sum(1/(2*k-1)^(2*n), k=1..infinity)/Pi^(2*n)), n=1..22);
MATHEMATICA
a[n_]:=Numerator[Pi^(-2 n) (1-2^(-2 n)) Zeta[2 n]] (* Steven Foster Clark, Mar 10 2023 *)
a[n_]:=Numerator[(-1)^n SeriesCoefficient[1/(E^x+1), {x, 0, 2 n-1}]] (* Steven Foster Clark, Mar 10 2023 *)
a[n_]:=Numerator[(-1)^n Residue[Zeta[s] Gamma[s] (1-2^(1-s)), {s, 1-2 n}]] (* Steven Foster Clark, Mar 11 2023 *)
KEYWORD
nonn,frac
AUTHOR
Martin Renner, Sep 07 2016
STATUS
approved
Denominator of the rational part of the sum of reciprocals of even powers of even numbers, i.e., Sum_{k>=1} 1/(2*k)^(2*n).
+0
4
24, 1440, 60480, 2419200, 95800320, 2615348736000, 149448499200, 21341245685760000, 10218188434341888000, 1605715325396582400000, 28202200078783610880000, 3387648273463487338905600000, 372269041039943663616000000, 75786531374911731038945280000000
OFFSET
1,1
COMMENTS
Denominator of Bernoulli(2*n)/(2*(2*n)!). - Robert Israel, Sep 18 2016
LINKS
FORMULA
A276592(n)/A276593(n) + A276594(n)/a(n) = A046988(n)/A002432(n).
Zeta(2n) = (-1)^(n-1)*(A276594(n)/a(n))*((2*Pi)^(2n)), according to Euler. - Terry D. Grant, Jun 19 2018
MAPLE
seq(denom(sum(1/(2*k)^(2*n), k=1..infinity)/Pi^(2*n)), n=1..24);
seq(denom(bernoulli(2*n)/2/(2*n)!), n=1..24); # Robert Israel, Sep 18 2016
MATHEMATICA
Table[Denominator[Zeta[2*n]/(2*Pi)^(2*n)], {n, 1, 30}] (* Terry D. Grant, Jun 19 2018 *)
PROG
(PARI) a(n) = denominator(bernfrac(2*n)/(2*(2*n)!)); \\ Michel Marcus, Jul 05 2018
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Martin Renner, Sep 07 2016
STATUS
approved
Numerator of the rational part of the sum of reciprocals of even powers of even numbers, i.e., Sum_{k>=1} 1/(2*k)^(2*n).
+0
3
1, 1, 1, 1, 1, 691, 1, 3617, 43867, 174611, 77683, 236364091, 657931, 3392780147, 1723168255201, 7709321041217, 151628697551, 26315271553053477373, 154210205991661, 261082718496449122051, 1520097643918070802691, 2530297234481911294093
OFFSET
1,6
FORMULA
A276592(n)/A276593(n) + a(n)/A276595(n) = A046988(n)/A002432(n).
MAPLE
seq(numer(sum(1/(2*k)^(2*n), k=1..infinity)/Pi^(2*n)), n=1..24);
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Martin Renner, Sep 07 2016
STATUS
approved

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