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 A308894 #5 Jul 01 2019 23:10:11 %S A308894 18,19,23,27,28,29,33,34,39,40,46,47,53,60,61,77,102,109,119,125,129, %T A308894 131,147,154,159,160,161,167,173,175,177,185,186,187,189,190,192,193, %U A308894 194,200,207,219,237,287,293,297,299,303,327,333,334,340,345,346,351,359,365,371,373,383,384,390,391,397,398 %N A308894 Positions of 3's on the spiral defined in A308890. %C A308894 Add 1 to the terms of A308888. %Y A308894 Cf. A308884-A308895. %K A308894 nonn %O A308894 1,1 %A A308894 _N. J. A. Sloane_, Jul 01 2019