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 A363889 #16 Jun 27 2023 07:05:37
%S A363889 1,5,8,11,14,21,20,23,26,40,32,35,38,55,44,47,57,70,56,59,62,85,68,88,
%T A363889 74,100,80,83,86,115,112,95,98,140,104,107,110,168,116,119,122,160,
%U A363889 128,154,160,175,140,143,146,190,152,184,158,231,164,167,183,220,208,179,182,235,188
%N A363889 Sum of divisors of 3*n-2 of form 3*k+1.
%H A363889 Seiichi Manyama, <a href="/A363889/b363889.txt">Table of n, a(n) for n = 1..10000</a>
%F A363889 a(n) = A078181(3*n-2).
%F A363889 G.f.: Sum_{k>0} (3*k-2) * x^k/(1 - x^(3*k-2)).
%t A363889 a[n_] := DivisorSum[3*n - 2, # &, Mod[#, 3] == 1 &]; Array[a, 100] (* _Amiram Eldar_, Jun 26 2023 *)
%o A363889 (PARI) a(n) = sumdiv(3*n-2, d, (d%3==1)*d);
%Y A363889 Cf. A363514, A363890, A363891.
%Y A363889 Cf. A078181, A359212.
%K A363889 nonn
%O A363889 1,2
%A A363889 _Seiichi Manyama_, Jun 26 2023