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 A328223 #16 Sep 08 2022 08:46:24
%S A328223 0,1,4,5,9,13,16,25,32,36,37,41,45,49,61,64,68,81,85,97,100,109,113,
%T A328223 117,121,144,145,149,153,160,169,181,193,196,208,221,225,229,241,256,
%U A328223 257,261,265,277,288,289,292,313,320,324,333,349,356,361,365,369,373,388,397,400
%N A328223 Numbers k such that both k and k+4 are sums of two squares.
%t A328223 ok[n_] := AllTrue[{0, 4}, SquaresR[2, # + n] > 0 &]; Select[Range[0, 400], ok] (* _Giovanni Resta_, Oct 08 2019 *)
%o A328223 (Magma) [k: k in [0..400] | NormEquation(1, k) eq true and NormEquation(1, k+4) eq true]; // _Marius A. Burtea_, Oct 08 2019
%Y A328223 Subsequence of A001481. Contains A328224 as a subsequence.
%Y A328223 Cf. A140612, A082982, A304441.
%K A328223 nonn
%O A328223 1,3
%A A328223 _Max Alekseyev_, Oct 08 2019