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 A079223 #4 Oct 17 2015 08:36:23 %S A079223 1,1,2,5,11,26,66,161,420,1093,2916,7819,21304,58321,161233,448090, %T A079223 1253252,3521389,9941693,28175716,80152141,228747967,654817275, %U A079223 1879602446,5408974390,15601662378,45098766532,130624550412 %N A079223 Number of Catalan objects fixed by two-fold application of the Catalan bijections A057511/A057512 (Deep rotation of general parenthesizations/plane trees). %F A079223 a(n) = A079216(n, 2) %p A079223 A079223 := n -> A079216bi(n,2); %Y A079223 The second row of A079216. The leftmost edge of the triangle A079218 and also its row sums shifted by one. Occurs for first time in A073202 as row 245. Cf. A057546, A079224, A079225, A079226, A079227. %K A079223 nonn %O A079223 0,3 %A A079223 _Antti Karttunen_ Jan 03 2002