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 A089279 #7 Oct 19 2017 03:14:26 %S A089279 1,3,2,5,4,6,5,9,8,10,9,12,11,13,12,17,16,18,17,20,19,21,20,24,23,25, %T A089279 24,27,26,28,27,33,32,34,33,36,35,37,36,40,39,41,40,43,42,44,43,48,47, %U A089279 49,48,51,50,52,51,55,54,56,55,58,57,59,58,65,64,66,65,68,67,69,68,72 %N A089279 a(n) = 2 + sum(k=1 to n) [(-1)^k A001511(k)]. %C A089279 a(2^n) = 2^n+1. %F A089279 a(2n+1) = A101925(n), a(2n+2) = a(2n+3)+1. - _Ralf Stephan_, Dec 28 2004 %Y A089279 Cf. A001511, A005187, A101925. %K A089279 nonn %O A089279 1,2 %A A089279 _Gary W. Adamson_, Oct 28 2003 %E A089279 Edited by _Don Reble_, Nov 15 2005