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A123713
Signature permutation of a nonrecursive Catalan automorphism: row 1783367 of table A089840.
3
0, 1, 2, 3, 4, 5, 7, 8, 6, 9, 10, 11, 12, 13, 17, 18, 20, 21, 22, 16, 19, 14, 15, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 45, 46, 48, 49, 50, 54, 55, 57, 58, 59, 61, 62, 63, 64, 44, 47, 53, 56, 60, 42, 51, 37, 38, 43, 52, 39, 40, 41, 65, 66, 67, 68, 69, 70, 71
OFFSET
0,3
PROG
(Scheme function, destructive implementation of this automorphism acting on S-expressions:) (define (*A123713! s) (cond ((not (pair? s)) s) ((pair? (car s)) (let ((org_cdar (cdar s))) (set-cdr! (car s) (cdr s)) (set-cdr! s (caar s)) (set-car! (car s) org_cdar) s)) ((and (pair? (cdr s)) (pair? (cadr s)) (pair? (caadr s)) (pair? (caaadr s))) (let ((org_b (car (caaadr s)))) (set-car! (caaadr s) (cdr (caaadr s))) (set-cdr! (caaadr s) (cdaadr s)) (set-cdr! (caadr s) (cdadr s)) (set-cdr! (cadr s) (cddr s)) (set-cdr! (cdr s) org_b) s)) (else s)))
CROSSREFS
Inverse: A123714. Row 1783367 of A089840. Differs from A089855 for the first time at n=102, where a(n)=103, while A089855(n)=102.
Sequence in context: A306012 A082352 A122320 * A089855 A122315 A130938
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 11 2006
STATUS
approved