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A250251 Fixed points of A250249 and A250250. 5
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 (list; graph; refs; listen; history; text; internal format)
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: A179239 A287478 A135579 * A138234 A324720 A247756

Adjacent sequences:  A250248 A250249 A250250 * A250252 A250253 A250254

KEYWORD

nonn

AUTHOR

Antti Karttunen, Nov 18 2014

STATUS

approved

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Last modified May 30 00:10 EDT 2020. Contains 334710 sequences. (Running on oeis4.)