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
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).
Programs
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Magma
[2^(3 + Valuation(n,2)): n in [1..80]]; // G. C. Greubel, Nov 01 2018
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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
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Mathematica
a[n_] := 8*BitAnd[n, -n]; Table[a[n], {n, 1, 81}] (* Jean-François Alcover, Sep 20 2011, after Joerg Arndt *) -
PARI
a(n)=if(n<1,0,8*2^valuation(n,2))
Extensions
More terms from James Sellers, Jun 20 2000