A245823 Fixed points of A245821 and A245822.

1, 2, 3, 4, 5, 7, 11, 17, 24, 31, 59, 89, 127, 184, 277, 461, 669, 709, 1097, 1787, 1995, 3259, 4999, 5381, 8807, 15299, 17351, 30133, 48593, 52711, 60810, 91081, 167449, 192263

Offset: 1

Author

Antti Karttunen, Aug 02 2014

Keywords

• nonn

Comments

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 nonprime terms: 1, 4, 24, 184, 669, 1995, 60810, ..., and is obtained as a union of prime recurrences that start with those values: A007097 U A057450 U ..., etc.

Crossrefs

A007097 and A057450 are subsequences.

Cf. A000040, A245821, A245822.

Programs

PARI

default(primelimit, 2^30);for(n=1, 2^18, if(A245821(n) == n, print1(n, ", "))); \\ Other code as in A245821.

Scheme

;; With Antti Karttunen's IntSeq-library.
(define A245823 (FIXED-POINTS 1 1 A245821))