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

1,2

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.

Links

Table of n, a(n) for n=1..34.

Prog

(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))

Crossrefs

A007097 and A057450 are subsequences.

Cf. A000040, A245821, A245822.

Sequence in context: A358876 A006456 A018134 * A143284 A343305 A346076

Adjacent sequences: A245820 A245821 A245822 * A245824 A245825 A245826

Keyword

nonn

Author

Antti Karttunen, Aug 02 2014

Status

approved