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 A241030 #14 Sep 08 2022 08:46:07
%S A241030 4,42,850,19782,485554,12252702,313742650,8094558822,209642795554,
%T A241030 5440108178862,141304954146250,3672136647383862,95452254746808754,
%U A241030 2481455748310337022,64513912079682866650,1677310528178740048902,43609408316038057305154
%N A241030 Sum of n-th powers of divisors of 26.
%H A241030 Vincenzo Librandi, <a href="/A241030/b241030.txt">Table of n, a(n) for n = 0..200</a>
%H A241030 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (42,-457,1092,-676).
%F A241030 G.f.: 2*(2 - 63*x + 457*x^2 - 546*x^3)/((1 - x)*(1 - 2*x)*(1 - 13*x)*(1 - 26*x)).
%F A241030 a(n) = (1 + 2^n)*(1 + 13^n).
%t A241030 Total[#^Range[0, 20] & /@ Divisors[26]] (* or *) Table[(1 + 2^n) (1 + 13^n), {n, 0, 20}]
%o A241030 (Magma) [DivisorSigma(n, 26): n in [0..20]];
%Y A241030 Cf. similar sequences listed in A241029.
%K A241030 nonn,easy
%O A241030 0,1
%A A241030 _Vincenzo Librandi_, Apr 17 2014