A127286 Signature-permutation of a Catalan automorphism: ENIPS-transformation of *A057508.

0, 1, 2, 3, 4, 6, 5, 7, 8, 9, 11, 14, 16, 19, 10, 15, 12, 17, 18, 13, 20, 21, 22, 23, 28, 25, 30, 33, 37, 39, 42, 44, 47, 51, 53, 56, 60, 24, 29, 38, 43, 52, 26, 40, 31, 45, 46, 32, 48, 49, 50, 27, 41, 34, 54, 55, 35, 57, 58, 59, 36, 61, 62, 63, 64, 65, 70, 79, 84, 93, 67, 81

Offset

0,3

Comments

ENIPS-transformation is explained in A122204. This automorphism permutes the top-level of a list of even length (1 ... 2n) as (2 4 6 ... 2n-2 2n 2n-1 2n-3 ... 5 3 1) and when applied to a list of odd length (1 .. 2n+1), permutes it as (2 4 6 ... 2n-2 2n 2n+1 2n-1 2n-3 ... 5 3 1). Used to construct A127288.

Links

Table of n, a(n) for n=0..71.

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 (*A127286! s) (cond ((pair? s) (*A127286! (cdr s)) (*A057508! s))) s)

Crossrefs

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

Sequence in context: A129605 A057509 A130919 * A130946 A073284 A057511

Adjacent sequences: A127283 A127284 A127285 * A127287 A127288 A127289

Keyword

nonn

Author

Antti Karttunen, Jan 16 2007

Status

approved