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 A359212 #13 Aug 23 2023 08:42:11
%S A359212 1,2,2,2,2,3,2,2,2,4,2,2,2,4,2,2,3,4,2,2,2,4,2,4,2,4,2,2,2,4,4,2,2,5,
%T A359212 2,2,2,6,2,2,2,4,2,4,4,4,2,2,2,4,2,4,2,6,2,2,3,4,4,2,2,4,2,4,2,6,2,2,
%U A359212 2,6,2,2,4,6,2,2,2,4,2,4,2,4,4,4,2,5,4,2,2,4
%N A359212 Number of divisors of 3*n-2 of form 3*k+1.
%F A359212 G.f.: Sum_{k>0} x^k/(1 - x^(3*k-2)).
%t A359212 a[n_] := DivisorSum[3*n-2, 1 &, Mod[#, 3] == 1 &]; Array[a, 100] (* _Amiram Eldar_, Aug 23 2023 *)
%o A359212 (PARI) a(n) = sumdiv(3*n-2, d, d%3==1);
%o A359212 (PARI) my(N=100, x='x+O('x^N)); Vec(sum(k=1, N, x^k/(1-x^(3*k-2))))
%Y A359212 Cf. A001817, A359211.
%K A359212 nonn,easy
%O A359212 1,2
%A A359212 _Seiichi Manyama_, Dec 21 2022