A244152 Self-inverse permutation of natural numbers: a(1) = 1; thereafter, if n is k-th number with an odd number of prime divisors (counted with multiplicity) [i.e., n = A026424(k)], a(n) = A028260(1+a(k)), otherwise, when n is k-th number > 1 with an even number of prime divisors [i.e., n = A028260(1+k)], a(n) = A026424(a(k)).

1, 4, 10, 2, 24, 7, 6, 55, 18, 3, 16, 15, 121, 44, 12, 11, 39, 9, 36, 35, 105, 31, 250, 5, 29, 28, 93, 26, 25, 86, 22, 82, 238, 79, 20, 19, 81, 72, 17, 68, 218, 65, 517, 14, 62, 67, 60, 202, 195, 57, 59, 56, 185, 477, 8, 52, 50, 175, 51, 47, 177, 45, 495, 167, 42, 161, 46, 40, 162, 169, 150, 38, 143, 455, 459, 140, 153, 1060, 34, 134, 37, 32

Offset

1,2

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 A066829(n) = 1, then a(n) = A028260(1 + A244152(A055038(n))), otherwise a(n) = A026424(A244152(A055037(n)-1)).

For all n > 1, A008836(a(n)) = -1 * A008836(n), where A008836 is Liouville's lambda-function.

Prog

(Scheme, with memoization macro definec)
(definec (A244152 n) (cond ((= 1 n) 1) ((= 1 (A066829 n)) (A028260 (+ 1 (A244152 (A055038 n))))) (else (A026424 (A244152 (-1+ (A055037 n)))))))

Crossrefs

Cf. A008836, A026424, A028260, A055037, A055038, A066829.

Similar entanglement permutations: A245603-A245604, A235491, A236854, A243347, A244319.

Sequence in context: A048870 A337840 A349305 * A070261 A367029 A054048

Adjacent sequences: A244149 A244150 A244151 * A244153 A244154 A244155

Keyword

nonn

Author

Antti Karttunen, Jul 27 2014

Status

approved