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 A363359 #16 Jul 08 2023 08:04:59
%S A363359 3,7,11,18,19,23,30,31,42,42,43,47,54,66,59,73,67,71,93,79,83,90,98,
%T A363359 114,113,103,107,114,138,126,126,127,131,180,139,154,157,151,186,162,
%U A363359 163,167,193,217,179,186,198,191,252,199,210,233,211,258,222,223,227,252,282,239,273,266,251,324,266,263,270
%N A363359 Sum of divisors of 4*n-1 of form 4*k+3.
%F A363359 a(n) = A050452(4*n-1).
%F A363359 G.f.: Sum_{k>0} (4*k-1) * x^k / (1 - x^(4*k-1)).
%t A363359 a[n_] := DivisorSum[4*n - 1, # &, Mod[#, 4] == 3 &]; Array[a, 100] (* _Amiram Eldar_, Jul 08 2023 *)
%o A363359 (PARI) a(n) = sumdiv(4*n-1, d, (d%4==3)*d);
%Y A363359 Cf. A050452, A078703, A364085.
%K A363359 nonn
%O A363359 1,1
%A A363359 _Seiichi Manyama_, Jul 08 2023