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 A054068 #7 Mar 30 2012 18:57:01 %S A054068 1,3,2,5,4,6,8,10,7,9,15,12,14,11,13,20,17,19,16,21,18,26,23,28,25,22, %T A054068 27,24,33,30,35,32,29,34,31,36,41,38,43,40,45,37,42,39,44,50,55,47,52, %U A054068 49,54,46,51,48,53,60,65,57,62,59,64,56,61 %N A054068 Permutation of N = set of natural numbers: a(n)+C(k,2), where a=A054065 and k=Floor((1+sqrt(8n-3))/2). %H A054068 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %e A054068 Referring to A054065, just add C(k,2) to the numbers in p(k): e.g. p(1)=(1)->(1); p(2)=(2,1)->(3,2); p(3)=(2,1,3)->(5,4,6). %Y A054068 Inverse permutation: A054069. %K A054068 nonn %O A054068 1,2 %A A054068 _Clark Kimberling_