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 A181672 #7 Mar 14 2014 02:02:02 %S A181672 1,3,2,3,3,5,4,4,5,4,6,3,7,5,8,5,9,4,10,3,11,6,12,6,13,8,14,8,15,7,16, %T A181672 7,17,9,18,8,19,8,20,6,21,9,22,9,23,11,24,10,25,10,26,9,27,11,28,11, %U A181672 29,10,30,6,31,9,32,9,33,11,34,10 %N A181672 The odd terms (a1,a3,a5,...) are in an arithmetic progression (1,2,3,...), while the even terms (a2,a4,a6,...) give the number of letters of the given odd term. %F A181672 a(2n-1) = n. %F A181672 a(2n) = A005589(n). %e A181672 (ONE - 3 letters, TWO - 3 letters, THREE - 5 letters, FOUR - 4 letters, FIVE - 4 letters...) %K A181672 nonn,word,easy %O A181672 1,2 %A A181672 _Edwin F. Sampang_, Nov 04 2010 %E A181672 More terms from _Nathaniel Johnston_, Nov 15 2010