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 A276956 #6 Sep 24 2016 10:50:12 %S A276956 1,2,3,6,10,4,15,5,21,28,36,9,45,14,55,66,78,91,105,120,136,153,171,7, %T A276956 190,20,210,231,253,8,276,27,300,325,351,35,378,44,406,435,465,496, %U A276956 528,561,595,630,666,13,703,54,741,780,820,19,861,65,903,946,990,77,1035,90,1081,1128,1176,1225,1275,1326,1378,1431,1485,104 %N A276956 Inverse permutation to A276955. %H A276956 Antti Karttunen, <a href="/A276956/b276956.txt">Table of n, a(n) for n = 1..10000</a> %H A276956 <a href="/index/Fa#facbase">Index entries for sequences related to factorial base representation</a> %H A276956 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A276956 a(n) = (1/2) * ((c+r)^2 - r - 3*c + 2), where c = A276949(n), and r = A276951(n). %F A276956 As a composition of other permutations: %F A276956 a(n) = A257506(A275847(n)). %o A276956 (Scheme) (define (A276956 n) (let ((row (A276951 n)) (col (A276949 n))) (* (/ 1 2) (- (expt (+ row col) 2) row col col col -2)))) %Y A276956 Inverse: A276955. %Y A276956 Cf. A276949, A276951. %Y A276956 Related permutations: A257506, A275847. %K A276956 nonn,base %O A276956 1,2 %A A276956 _Antti Karttunen_, Sep 22 2016