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A123694 a(n) gives the A089840-index of the nonrecursive Catalan automorphism which is formed from A089840[n] by applying it to the left subtree of a binary tree and leaving the right-hand side subtree intact. 4
0, 7, 91, 92, 93, 94, 95, 114, 115, 116, 117, 118, 4207, 4209, 4211, 4214, 4216, 4299, 4301, 4303, 4305, 4307, 1228, 1229, 1230, 1231, 1232, 1233, 1234, 1235, 1236, 1237, 1238, 1239, 1240, 1241, 1242, 1243, 1244, 1245, 1246, 1247, 1248, 1249, 1250, 1347 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

If the count of fixed points of the automorphism A089840[n] is given by sequence f, then the count of fixed points of the automorphism A089840[A123694(n)] is given by CONV(f,A000108) (where CONV stands for convolution). See also the comments at A122200.

LINKS

Table of n, a(n) for n=0..45.

A. Karttunen, C-program for computing the initial terms of this sequence

A. Karttunen, Prolog-program which illustrates the nonrecursive Catalan automorphisms given on example-lines.

EXAMPLE

When A089840[1] = A069770 (swap binary tree sides) is applied to the left subtree of a binary tree, we get A089840[7] = A089854, thus a(1)=7. When A089840[12] = A074679 is applied to the left subtree of a binary tree, we get A089840[4207] = A089865, thus a(12)=4207.

CROSSREFS

Sequence in context: A306137 A226624 A266236 * A319978 A085026 A221132

Adjacent sequences:  A123691 A123692 A123693 * A123695 A123696 A123697

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 11 2006

STATUS

approved

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Last modified December 7 09:33 EST 2019. Contains 329843 sequences. (Running on oeis4.)