A250251 Fixed points of A250249 and A250250.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38, 40, 41, 43, 44, 46, 47, 48, 49, 50, 52, 53, 56, 58, 59, 60, 61, 62, 64, 67, 68, 70, 71, 72, 74, 76, 77, 79, 80, 82, 83, 86, 88, 89, 92, 94, 96, 97, 98, 100, 101, 104, 106, 107, 109, 112, 113, 116, 118, 120, 121

Offset

1,2

Comments

Numbers for which A250249(n) = n (equally: A250250(n) = n).

If n is a member, then 2n is also a member. If any 2n is a member, then n is also a member. If n is a member, then the n-th prime, p_n (= A000040(n)) is also a member. If p_n is a member, then its index n is also a member. Thus the sequence is completely determined by its odd nonprime terms: 1, 9, 15, 25, ..., (A249730) and is obtained as a union of their multiples with powers of 2, and all prime recurrences that start with those values: A007097 U A057450 U A057451 U A057452 U A057453 U ..., etc.

Links

Antti Karttunen, Table of n, a(n) for n = 1..801

Prog

(Scheme, with Antti Karttunen's IntSeq-library)
(define A250251 (FIXED-POINTS 1 1 A250249))

Crossrefs

Complement: A249729.

Subsequences: A249730, and also A007097, A057450, A057451, A057452, A057453, etc.

Cf. also A245823, A250249, A250250.

Sequence in context: A287478 A336358 A135579 * A138234 A324720 A374847

Adjacent sequences: A250248 A250249 A250250 * A250252 A250253 A250254

Keyword

nonn

Author

Antti Karttunen, Nov 18 2014

Status

approved