A079223 Number of Catalan objects fixed by two-fold application of the Catalan bijections A057511/A057512 (Deep rotation of general parenthesizations/plane trees).

1, 1, 2, 5, 11, 26, 66, 161, 420, 1093, 2916, 7819, 21304, 58321, 161233, 448090, 1253252, 3521389, 9941693, 28175716, 80152141, 228747967, 654817275, 1879602446, 5408974390, 15601662378, 45098766532, 130624550412

Offset: 0

Author

Antti Karttunen Jan 03 2002

Keywords

• nonn

Crossrefs

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.

Programs

Maple

A079223 := n -> A079216bi(n,2);

Formula

a(n) = A079216(n, 2)