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 A161338 #6 Jul 31 2021 01:59:34 %S A161338 0,3,6,9,18,21,30,39,48,63,72,87,108,111,120,129,144,171,186,225,246, %T A161338 273,312,333,366,405,414,435,456,483,528,561,624,669,714,765,798,837, %U A161338 882,927,972,999,1032,1089,1128,1191,1254,1305,1356,1425,1476,1557,1608 %N A161338 a(n) = (A161330(n+1) - 2)/2. %Y A161338 Cf. A161330, A161331, A161336, A161337. %K A161338 nonn %O A161338 0,2 %A A161338 _Omar E. Pol_, Jun 09 2009 %E A161338 More terms from _Jinyuan Wang_, Jul 30 2021