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 A265346 #5 Dec 29 2015 03:19:47 %S A265346 1,3,2,6,7,5,4,10,11,8,46,9,22,38,56,15,79,17,29,13,16,12,191,14,37, %T A265346 30,92,18,379,23,172,28,407,212,667,24,232,278,67,19,1654,155,301,69, %U A265346 704,47,466,20,121,353,497,39,781,107,254,25,137,57,2081,31,277,192,106,21,1541,68,211,58,1082,93,1712,32,326,255,154,48,2702,80,352,26,821 %N A265346 Inverse permutation to A265345. %H A265346 Antti Karttunen, <a href="/A265346/b265346.txt">Table of n, a(n) for n = 1..10328</a> %H A265346 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A265346 a(n) = (1/2) * ((c+r)^2 - r - 3*c + 2), where c = A265911(n), and r = A265331(n). %o A265346 (Scheme) (define (A265346 n) (let ((col (A265911 n)) (row (A265331 n))) (* (/ 1 2) (- (expt (+ row col) 2) row col col col -2)))) %Y A265346 Inverse: A265345. %Y A265346 Cf. A265331, A265911. %K A265346 nonn %O A265346 1,2 %A A265346 _Antti Karttunen_, Dec 18 2015