A269857 Permutation of natural numbers: a(1) = 1; if n is an odd prime, a(n) = A250469(a(A026233(n))), else a(n) = 2*(a(A026233(n))).

1, 2, 3, 4, 5, 6, 9, 8, 10, 12, 7, 18, 15, 16, 20, 24, 25, 14, 21, 36, 30, 32, 27, 40, 48, 50, 28, 42, 33, 72, 11, 60, 64, 54, 80, 96, 51, 100, 56, 84, 35, 66, 45, 144, 22, 120, 57, 128, 108, 160, 192, 102, 69, 200, 112, 168, 70, 132, 49, 90, 39, 288, 44, 240, 114, 256, 55, 216, 320, 384, 105, 204, 87, 138, 400

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..2662

Index entries for sequences that are permutations of the natural numbers

Formula

a(1) = 1; if n is an odd prime, a(n) = A250469(a(A026233(n))), else a(n) = 2*(a(A026233(n))).

As a composition of other permutations:

a(n) = A252755(A071574(n)).

Prog

(Scheme, with memoization-macro definec)
(definec (A269857 n) (cond ((<= n 1) n) ((and (odd? n) (= 1 (A010051 n))) (A250469 (A269857 (A026233 n)))) (else (A005843 (A269857 (A026233 n))))))

Crossrefs

Inverse: A269858.

Cf. A005843, A026233, A010051, A250469.

Related or similar permutations: A071574, A252755, A269847.

Differs from A269847 for the first time at n=19, where a(19)=21, while A269847(19)=27.

Sequence in context: A005941 A355460 A355809 * A269847 A358522 A279407

Adjacent sequences: A269854 A269855 A269856 * A269858 A269859 A269860

Keyword

nonn

Author

Antti Karttunen, Mar 06 2016

Status

approved