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A130339
Signature permutation of a Catalan automorphism: swap the two rightmost subtrees of general trees, if the root degree (A057515(n)) is even.
4
0, 1, 2, 3, 4, 6, 5, 7, 8, 9, 10, 11, 16, 19, 14, 15, 12, 17, 18, 13, 20, 21, 22, 23, 25, 24, 26, 27, 28, 29, 30, 44, 47, 33, 53, 56, 60, 37, 38, 39, 43, 52, 42, 40, 31, 45, 46, 32, 48, 49, 50, 51, 41, 34, 54, 55, 35, 57, 58, 59, 36, 61, 62, 63, 64, 65, 66, 67, 72, 75, 70, 71
OFFSET
0,3
COMMENTS
This self-inverse automorphism is obtained as either SPINE(*A129608) or ENIPS(*A129608). See the definitions given in A122203 and A122204.
PROG
(Destructive Scheme implementation of this automorphism, which acts on S-expressions, i.e. list-structures:)
(define (*A130339! s) (if (even? (length s)) (*A129608! s)) s)
CROSSREFS
Cf. a(n) = A057508(A130340(A057508(n))) = A057164(A130340(A057164(n))). Row 3608 of A122285 and A122286. a(n) = A129608(n), if A057515(n) mod 2 = 0, otherwise a(n)=n.
Sequence in context: A275582 A129607 A130340 * A350348 A058812 A320454
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 05 2007
STATUS
approved