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 A363880 #11 Jun 25 2023 10:39:52
%S A363880 0,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,3,0,0,1,0,1,1,0,0,1,2,0,2,0,0,2,0,
%T A363880 0,1,0,2,1,0,0,2,1,0,1,0,1,3,0,0,1,0,1,2,0,0,1,2,0,1,0,0,2,1,0,3,0,2,
%U A363880 1,0,0,1,1,0,1,0,0,4,0,0,2,0,1,1,1,0,1,2,0,3,0,0,2,0,0,1,0,3,1,0
%N A363880 Number of divisors of 7*n-6 of form 7*k+3.
%C A363880 Also number of divisors of 7*n-6 of form 7*k+5.
%F A363880 a(n) = A363805(7*n-6) = A363807(7*n-6).
%F A363880 G.f.: Sum_{k>0} x^(5*k-2)/(1 - x^(7*k-4)).
%F A363880 G.f.: Sum_{k>0} x^(3*k)/(1 - x^(7*k-2)).
%t A363880 a[n_] := DivisorSum[7*n - 6, 1 &, Mod[#, 7] == 3 &]; Array[a, 100] (* _Amiram Eldar_, Jun 25 2023 *)
%o A363880 (PARI) a(n) = sumdiv(7*n-6, d, d%7==3);
%Y A363880 Cf. A363805, A363807.
%K A363880 nonn
%O A363880 1,18
%A A363880 _Seiichi Manyama_, Jun 25 2023