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 A103637 #10 Jun 30 2023 12:44:25
%S A103637 1,1,1,17,1,1,50,17,1,101,1,17,170,50,1,273,1,1,362,117,50,485,1,17,
%T A103637 626,170,1,850,1,101,962,273,1,1157,50,17,1370,362,170,1717,1,50,1850,
%U A103637 501,1,2117,1,273,2451,726,1,2890,1,1,3026,850,362,3365,1,117,3722
%N A103637 a(n) = Sum_{d|n, d==1 mod 3} d^2.
%H A103637 Seiichi Manyama, <a href="/A103637/b103637.txt">Table of n, a(n) for n = 1..10000</a>
%t A103637 a[n_] := DivisorSum[n, #^2 &, Mod[#, 3] == 1 &]; Array[a, 100] (* _Amiram Eldar_, Jun 30 2023 *)
%o A103637 (PARI) a(n) = sumdiv(n, d, (d%3==1)*d^2); \\ _Seiichi Manyama_, Jun 30 2023
%K A103637 nonn
%O A103637 1,4
%A A103637 _Ralf Stephan_, Feb 11 2005