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 A254108 #6 Feb 06 2015 02:49:01 %S A254108 1,3,2,4,6,5,7,11,8,16,22,10,9,12,29,37,17,46,56,13,23,67,79,30,92, %T A254108 106,15,14,18,38,121,137,47,154,172,24,57,191,211,68,232,254,19,31,80, %U A254108 277,301,93,326,352,39,107,379,407,122,436,466,21,20,25,48,138,497,529,155,562,596,58,173,631,667,192,704,742,32,69,212 %N A254108 Inverse permutation to A254107. %H A254108 Antti Karttunen, <a href="/A254108/b254108.txt">Table of n, a(n) for n = 1..8192</a> %H A254108 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A254108 (Scheme) (define (A254108 n) (let ((col (A254111 n)) (row (A254112 n))) (* (/ 1 2) (- (expt (+ col row) 2) col row row row -2)))) %Y A254108 Inverse: A254107. %Y A254108 Cf. A254106, A254111, A254112. %K A254108 nonn %O A254108 1,2 %A A254108 _Antti Karttunen_, Jan 27 2015