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 A032609 #12 Feb 17 2024 10:29:40
%S A032609 15,26,37,48,59,610,711,812,913,1014,1115,1216,1317,1418,1519,1620,
%T A032609 1721,1822,1923,2024,2125,2226,2327,2428,2529,2630,2731,2832,2933,
%U A032609 3034,3135,3236,3337,3438,3539,3640,3741,3842,3943,4044,4145,4246
%N A032609 Concatenation of n and n + 4 or {n,n+4}.
%Y A032609 Cf. A001704, A020338.
%K A032609 nonn,base
%O A032609 1,1
%A A032609 _Patrick De Geest_, May 15 1998