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 A161209 #6 Mar 02 2020 00:53:06 %S A161209 1,2,3,4,5,6,7,6,6,9,12,15,15,14,15,10,6,9,13,17,21,25,28,27,22,24,32, %T A161209 41,40,34,33,18,6,9,13,17,21,25,29,29,27,33,45,57,63,61,60,51,30,24, %U A161209 35,47,59,71,80,81,68,65,80,102,99,80,71,34,6 %N A161209 a(n) = A161207(n+1)/2. %Y A161209 Cf. A161206, A161207, A161208. %K A161209 nonn,more %O A161209 1,2 %A A161209 _Omar E. Pol_, Jun 08 2009 %E A161209 More terms from _Jinyuan Wang_, Mar 01 2020