A127287 Signature-permutation of a Catalan automorphism: composition of A127285 and A057508.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 28, 24, 30, 33, 25, 29, 26, 31, 32, 27, 34, 35, 36, 37, 39, 38, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 79, 67, 84, 93, 66, 80

Offset

0,3

Comments

This automorphism permutes the top-level of a list of even length (1 ... 2n) as (1 2n 2 2n-1 3 2n-3 ... n n+1) and when applied to a list of odd length (1 .. 2n+1), permutes it as (1 2n+1 2 2n 3 2n-1 ... n n+1). Used to construct A127291.

Links

A. Karttunen, Table of n, a(n) for n = 0..2055

Index entries for signature-permutations of Catalan automorphisms

Prog

(Scheme implementation of this automorphism, destructive, that acts on S-expressions, i.e. list-structures:)
(define (*A127287! s) (*A127285! (*A057508! s)))

Crossrefs

Inverse: A127288. a(n) = A127285(A057508(n)).

Sequence in context: A031086 A363038 A127288 * A239088 A162344 A283962

Adjacent sequences: A127284 A127285 A127286 * A127288 A127289 A127290

Keyword

nonn

Author

Antti Karttunen, Jan 16 2007

Status

approved