A337609 Positive integers m such that A126286^k(m) = m for some positive integer k.

2, 3, 14, 21, 26, 34, 38, 39, 50, 57, 62, 74, 75, 85, 86, 93, 94, 98, 110, 111, 118, 122, 129, 134, 142, 146, 147, 154, 158, 165, 170, 182, 183, 194, 201, 202, 206, 214, 218, 219, 230, 235, 237, 242, 254, 255, 266, 273, 274, 278, 286, 290, 291, 298, 302, 309

Offset

1,1

Comments

A126286^k(m) means apply A126286 to m k times.

Equivalently, the numbers that belong to a cycle under the map x -> A126286(x).

For any term m in this sequence, A126286(A126286(m)) = m.

Supersequence of A017545. Moreover, this sequence can be represented as an infinite union of arithmetic progressions.

2 and 3 are the only primes in this sequence.

Links

Ely Golden, Table of n, a(n) for n = 1..10000

Ely Golden, Python program for generating terms of this sequence

Example

3 is a term since A126286(A126286(3)) = A126286(2) = 3.

Crossrefs

Cf. A017545, A126286, A337610, A337611, A337612.

Sequence in context: A294405 A160218 A208983 * A081615 A157903 A024478

Adjacent sequences: A337606 A337607 A337608 * A337610 A337611 A337612

Keyword

nonn,easy

Author

Ely Golden, Oct 07 2020

Status

approved