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 A117704 #8 Jul 13 2013 12:03:23 %S A117704 1,2,1,2,3,1,5,1,5,4,3,8,9,4,6,9,2,12,3,10,9,5,15,1,15,8,9,16,2,19,6, %T A117704 14,15,6,22,3,20,13,11,24,1,26,10,17,22,6,29,6,24,19,12,32,1,32,15,19, %U A117704 30,5,36,10,27,26,12,39,4,36,21,20,39,3,43,15,29,34,11,46,8,39,28,20,49,50 %N A117704 Least refined sequence that can be grouped to sum to either natural numbers or odd numbers. %C A117704 In other words, least common refinement of the natural numbers and the odd numbers. %H A117704 Reinhard Zumkeller, <a href="/A117704/b117704.txt">Table of n, a(n) for n = 1..10000</a> %F A117704 a(n) = A005214(n) - A005214(n-1). %e A117704 As natural numbers: 1,2,1+2,3+1,5,1+5,4+3,8,... %e A117704 As odd numbers: 1,2+1,2+3,1+5+1,5+4,3+8,... %o A117704 (Haskell) %o A117704 a117704 n = a117704_list !! (n-1) %o A117704 a117704_list = 1 : zipWith (-) (tail a005214_list) a005214_list %o A117704 -- _Reinhard Zumkeller_, Aug 03 2011 %Y A117704 Cf. A118382, A005214, A000027, A005408. %K A117704 nonn,easy %O A117704 1,2 %A A117704 _Franklin T. Adams-Watters_, Apr 27 2006