A245614 Permutation of natural numbers: a(1)=1; thereafter, if n is k-th number whose greatest prime factor has an odd index [i.e., n = A244991(k)], a(n) = A026424(a(k)), otherwise, when n is k-th number whose greatest prime factor has an even index [i.e., n = A244990(1+k)], a(n) = A028260(1+a(k)).

1, 2, 4, 3, 7, 6, 10, 5, 9, 12, 11, 16, 15, 24, 18, 8, 17, 14, 22, 20, 26, 19, 29, 25, 28, 36, 35, 55, 39, 44, 31, 13, 30, 27, 21, 38, 34, 51, 46, 42, 37, 57, 40, 47, 32, 52, 45, 62, 56, 50, 68, 60, 82, 81, 67, 121, 86, 93, 105, 72, 65, 79, 33, 59, 64, 23, 53, 48, 41, 58, 49, 85, 71, 77, 66, 111, 99

Offset

1,2

Comments

This shares with the permutation A122111 the property that each term of A244990 is mapped to a unique term of A028260 and each term of A244991 is mapped to a unique term of A026424.

Links

Antti Karttunen, Table of n, a(n) for n = 1..10001

Index entries for sequences that are permutations of the natural numbers

Formula

a(1) = 1, and for n > 1, if A244992(n) = 1, a(n) = A026424(a(A244989(n))), otherwise a(n) = A028260(1+a(A244988(n)-1)).

As a composition of related permutations:

a(n) = A245604(A244321(n)).

For all n >= 1, A244992(n) = A066829(a(n)).

Prog

(Scheme, with memoization macro definec)
(definec (A245614 n) (cond ((= 1 n) 1) ((= 1 (A244992 n)) (A026424 (A245614 (A244989 n)))) (else (A028260 (+ 1 (A245614 (-1+ (A244988 n))))))))

Crossrefs

Inverse: A245613.

Cf. A026424, A028260, A066829, A244988, A244989, A244990, A244991, A244992, A122111.

Similar permutations: A244321, A244322, A245604, A227413, A237126, A243288, A243344, A243346, A245606.

Sequence in context: A114537 A243349 A266413 * A246165 A260432 A021808

Adjacent sequences: A245611 A245612 A245613 * A245615 A245616 A245617

Keyword

nonn,look

Author

Antti Karttunen, Jul 27 2014

Status

approved