A037239 Numerator of Pi^(2n)/(GAMMA(2n)*(1-2^(-2n))*Zeta(2n)); = 8*(highest power of 2 dividing n).

8, 16, 8, 32, 8, 16, 8, 64, 8, 16, 8, 32, 8, 16, 8, 128, 8, 16, 8, 32, 8, 16, 8, 64, 8, 16, 8, 32, 8, 16, 8, 256, 8, 16, 8, 32, 8, 16, 8, 64, 8, 16, 8, 32, 8, 16, 8, 128, 8, 16, 8, 32, 8, 16, 8, 64, 8, 16, 8, 32, 8, 16, 8, 512, 8, 16, 8, 32, 8, 16, 8, 64, 8

Offset

1,1

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

Harvey Cohn, Some elementary aspects of modular functions in several variables, Bull. Amer. Math. Soc. 71 (1965), 681-704, (esp. p. 688).

Maple

with(numtheory): for n from 1 to 200 do if n mod 2 = 1 then printf(`%d, `, 8) else printf(`%d, `, 8*2^ifactors(n)[2][1][2]) fi; od:
seq(2^(3+padic[ordp](n, 2)), n=1..73); # Peter Luschny, Apr 03 2014

Mathematica

a[n_] := 8*BitAnd[n, -n]; Table[a[n], {n, 1, 81}] (* Jean-François Alcover, Sep 20 2011, after Joerg Arndt *)

Prog

(PARI) a(n)=if(n<1, 0, 8*2^valuation(n, 2))
(Magma) [2^(3 + Valuation(n, 2)): n in [1..80]]; // G. C. Greubel, Nov 01 2018

Crossrefs

Equals 8*A006519. Denominators given by A002425.

Sequence in context: A335772 A299214 A174256 * A205869 A217178 A103699

Adjacent sequences: A037236 A037237 A037238 * A037240 A037241 A037242

Keyword

nonn,frac,easy

Author

N. J. A. Sloane

Extensions

More terms from James A. Sellers, Jun 20 2000

Status

approved