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 A279926 #25 Dec 24 2016 02:03:47
%S A279926 0,1,522,24329,454250,4905766,36532244,207705929,961214238,3784166376,
%T A279926 13066960126,40511160326,114681233758,300599979884,737035375772,
%U A279926 1705830324553,3751239987240,7887626314003,15927815870322,31031953887704,58508991327728,107133058597170
%N A279926 a(n) = Sum_{k=1..n-1} sigma_3(k)*sigma_9(n-k).
%H A279926 Seiichi Manyama, <a href="/A279926/b279926.txt">Table of n, a(n) for n = 1..1000</a>
%F A279926 a(n) = (sigma_13(n) - 11*sigma_9(n) + 10*sigma_3(n))/2640.
%t A279926 Table[Sum[If[k == 0, 0, DivisorSigma[3, k]] DivisorSigma[9, n - k], {k, 0, n - 1}], {n, 22}] (* _Michael De Vlieger_, Dec 23 2016 *)
%o A279926 (PARI) a(n) = sum(k=1, n-1, sigma(k, 3)*sigma(n-k, 9)) \\ _Felix Fröhlich_, Dec 23 2016
%Y A279926 Cf. A001158, A013957, A013961, A279888, A279917.
%K A279926 nonn
%O A279926 1,3
%A A279926 _Seiichi Manyama_, Dec 23 2016