This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A091260 #18 Dec 20 2024 02:38:03
%S A091260 1,5,5,21,13,25,25,17,91,65,61,15,85,125,65,11,145,455,181,13,125,305,
%T A091260 265,85,651,425,41,525,421,325,481,455,305,725,325,1911,685,181,425,
%U A091260 17,841,625,925,427,169,1325,1105,55,817,1085,725,255,1405,205,793,425,181
%N A091260 Denominator of sigma_3(n)/sigma_2(n).
%C A091260 If n is an odd prime then a(n) = A001844((n-1)/2). - _Robert Israel_, Jan 26 2018
%H A091260 Harvey P. Dale, <a href="/A091260/b091260.txt">Table of n, a(n) for n = 1..1000</a>
%p A091260 seq(denom(numtheory:-sigma[3](n)/numtheory:-sigma[2](n)),n=1..100); # _Robert Israel_, Jan 26 2018
%t A091260 Denominator[Table[DivisorSigma[3,n]/DivisorSigma[2,n],{n,60}]] (* _Harvey P. Dale_, Nov 03 2011 *)
%o A091260 (PARI) a(n) = my(f = factor(n)); denominator(sigma(f, 3)/sigma(f, 2)); \\ _Amiram Eldar_, Dec 20 2024
%Y A091260 Cf. A001158, A001157, A000203, A091258, A091259, A298754 (numerator), A001844.
%K A091260 easy,nonn,frac
%O A091260 1,2
%A A091260 _Labos Elemer_, Feb 12 2004