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 A255122 #11 Feb 14 2015 21:30:56 %S A255122 0,1,3,2,6,5,4,11,10,9,8,7,20,19,18,17,16,15,14,13,12,36,35,34,33,32, %T A255122 31,30,29,28,27,26,25,24,23,22,21,65,64,63,62,61,60,59,58,57,56,55,54, %U A255122 53,52,51,50,49,48,47,46,45,44,43,42,41,40,39,38,37,118 %N A255122 Simple self-inverse permutation of natural numbers: after zero, list each block of A255071(n) numbers in reverse order, from A255061(n+1) to A255062(n). %C A255122 Maps between A255056 and A255066. (Equally, between A255057 and A255067.) %H A255122 Antti Karttunen, <a href="/A255122/b255122.txt">Table of n, a(n) for n = 0..721</a> %H A255122 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A255122 a(n) = A255061(1+A255121(n)) - A255120(n). %o A255122 (Scheme) (define (A255122 n) (- (A255061 (+ 1 (A255121 n))) (A255120 n))) %Y A255122 Cf. A255061, A255062, A255071, A255120, A255121. %Y A255122 Cf. A255056, A255057, A255066, A255067. %Y A255122 Similar permutations: A218602, A230432. %K A255122 nonn %O A255122 0,3 %A A255122 _Antti Karttunen_, Feb 14 2015