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 A065811 #5 Sep 15 2023 20:13:22 %S A065811 0,3,6,9,12,45,48,63,66,78,111,123,126,138,150,231,243,261,309,324, %T A065811 348,351,363,402,414,417,441,456,504,570,582,660,684,765,768,849,873, %U A065811 951,963,1056,1125,1431,1518,1551,1638,1944,2013,2049,2139,2433,2457,2511 %N A065811 a(n) = A065810(n)-1. %K A065811 nonn %O A065811 1,2 %A A065811 _Antti Karttunen_, Nov 22 2001