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 A050448 #20 Jul 08 2023 08:05:42
%S A050448 1,1,1,1,626,1,1,1,6562,626,1,1,28562,1,626,1,83522,6562,1,626,194482,
%T A050448 1,1,1,391251,28562,6562,1,707282,626,1,1,1185922,83522,626,6562,
%U A050448 1874162,1,28562,626,2825762,194482,1,1,4107812,1,1,1
%N A050448 a(n) = Sum_{d|n, d==1 (mod 4)} d^4.
%H A050448 Seiichi Manyama, <a href="/A050448/b050448.txt">Table of n, a(n) for n = 1..10000</a>
%t A050448 a[n_] := DivisorSum[n, #^4 &, Mod[#, 4] == 1 &]; Array[a, 50] (* _Amiram Eldar_, Jul 08 2023 *)
%o A050448 (PARI) a(n) = sumdiv(n, d, if ((d%4)==1, d^4)); \\ _Michel Marcus_, Aug 16 2021
%Y A050448 Cf. A001159, A050449, A050450, A050451.
%K A050448 nonn
%O A050448 1,5
%A A050448 _N. J. A. Sloane_, Dec 23 1999
%E A050448 Offset corrected by _Sean A. Irvine_, Aug 15 2021