A088839 Numerator of sigma(4n)/sigma(n).
7, 5, 7, 31, 7, 5, 7, 21, 7, 5, 7, 31, 7, 5, 7, 127, 7, 5, 7, 31, 7, 5, 7, 21, 7, 5, 7, 31, 7, 5, 7, 85, 7, 5, 7, 31, 7, 5, 7, 21, 7, 5, 7, 31, 7, 5, 7, 127, 7, 5, 7, 31, 7, 5, 7, 21, 7, 5, 7, 31, 7, 5, 7, 511, 7, 5, 7, 31, 7, 5, 7, 21, 7, 5, 7, 31, 7, 5, 7, 127, 7, 5, 7, 31, 7, 5, 7, 21, 7, 5, 7, 31
Offset: 1
Links
Crossrefs
Programs
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Maple
f:= proc(n) local m; m:= padic:-ordp(n,2); if m::odd then (2^(m+3)-1)/3 else 2^(m+3)-1 fi end proc: map(f, [$1..200]); # Robert Israel, Nov 19 2017
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Mathematica
k=4; Table[Numerator[DivisorSigma[1, k*n]/DivisorSigma[1, n]], {n, 1, 128}] -
PARI
A088839(n) = numerator(sigma(4*n)/sigma(n)); \\ Antti Karttunen, Nov 18 2017
Formula
From Amiram Eldar, Jan 06 2023: (Start)
Extensions
Typo in definition corrected by Antti Karttunen, Nov 18 2017
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