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 A261099 #10 Sep 24 2015 01:40:35 %S A261099 0,0,0,4,3,0,0,0,12,16,23,19,8,23,0,20,0,7,16,11,15,0,7,0,0,0,0,4,3,0, %T A261099 48,48,60,64,71,67,86,93,74,94,74,85,116,111,119,99,108,99,30,30,86, %U A261099 89,112,111,0,0,78,82,107,103,0,20,26,46,96,103,15,0,41,29,78,73,60,115,38,119,38,63,56,107,0,104,0,55,26,100,0,104,19,42,33,56,11,52,0,25 %N A261099 Main diagonal of A261096. %C A261099 Equally: main diagonal of A261097. %C A261099 For permutation p, which has rank n in permutation list A055089 (A195663), a(n) gives the rank of the "square" of that permutation (obtained by composing it with itself as: q(i) = p(p(i))) in the same list. Thus zeros (which mark the identity permutation, with rank 0) occur at positions where the permutations of A055089/A195663 are involutions, listed by A014489. %H A261099 Antti Karttunen, <a href="/A261099/b261099.txt">Table of n, a(n) for n = 0..5040</a> %F A261099 a(n) = A261096(n,n) = A261097(n,n). %F A261099 By conjugating a similar sequence: %F A261099 a(n) = A060119(A261219(A060126(n))). %Y A261099 Main diagonal of A261096 and A261097. %Y A261099 Cf. A014489 (the positions of zeros). %Y A261099 Cf. A055089, A195663. %Y A261099 Cf. also A261219. %Y A261099 Related permutations: A060119, A060126. %K A261099 nonn %O A261099 0,4 %A A261099 _Antti Karttunen_, Aug 26 2015