A279347 Self-inverse permutation of natural numbers: a(1) = 1, a(2) = 2, a(A055938(n)) = A005187(a(n)), a(A005187(n)) = A055938(a(n)).

1, 2, 5, 12, 3, 8, 27, 6, 22, 17, 58, 4, 15, 50, 13, 45, 10, 36, 121, 41, 32, 9, 30, 112, 103, 28, 7, 26, 97, 23, 92, 21, 86, 75, 248, 18, 70, 84, 65, 237, 20, 61, 79, 63, 16, 227, 210, 56, 59, 14, 221, 201, 55, 196, 53, 48, 187, 11, 49, 191, 42, 180, 44, 175, 39, 154, 503, 168, 146, 37, 141, 491, 171, 132, 34, 137, 165, 478, 43, 128

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..8192

Index entries for sequences that are permutations of the natural numbers

Formula

a(1) = 1, a(2) = 2, for n > 2, A079559(n) = 0 [when n is a term of A055938], a(n) = A005187(a(A256992(n))), otherwise a(n) = A055938(a(A256992(n))).

As a composition of other permutations:

a(n) = A279342(A279343(n)).

a(n) = A279344(A279341(n)).

Example

a(1) = 1 and a(2) = 2 by definition.
Because A005187(2) = 3, a(3) = A055938(a(2)) = 5, and vice versa, as A055938(2) = 5, a(5) = A005187(a(2)) = 3.
Because A005187(3) = 4, a(4) = A055938(a(3)) = A055938(5) = 12.
Because A055938(3) = 6, a(6) = A005187(a(3)) = A005187(5) = 8.

Prog

(Scheme) (definec (A279347 n) (cond ((<= n 2) n) ((zero? (A079559 n)) (A005187 (A279347 (A256992 n)))) (else (A055938 (A279347 (A256992 n))))))

Crossrefs

Cf. A005187, A055938, A079559, A256992.

Related or similar permutations: A279341, A279342, A279343, A279344.

Sequence in context: A286466 A127532 A127530 * A151574 A110020 A070266

Adjacent sequences: A279344 A279345 A279346 * A279348 A279349 A279350

Keyword

nonn

Author

Antti Karttunen, Dec 10 2016

Status

approved