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 A121865 #10 Sep 11 2023 10:25:46 %S A121865 1,2,4,6,7,9,17,20,24,26,29,33,35,36,37,38,42,47,49,52,55,56,61,64,68, %T A121865 70,71,72,74,75,78,79,85,86,89,91,95,101,105,106,107,108,110,113,114, %U A121865 120,124,126,127,129,131,133,135,141,142,147,148,150,151,152,153,156 %N A121865 Complement of A120943. %Y A121865 Cf. A120943. %K A121865 base,nonn %O A121865 1,2 %A A121865 _Robert G. Wilson v_, Aug 22 2006 %E A121865 Missing terms 1, 2, 6, 38 inserted by _Georg Fischer_, Sep 11 2023