A238855 Number of all right-truncatable reversible primes in base n.

0, 3, 4, 12, 5, 12, 24, 17, 16, 33, 22, 29, 50, 39, 40, 39, 24, 65, 80, 100, 58, 58, 69, 122, 101, 90, 83, 125, 114, 133, 114, 122, 255, 203, 252, 123, 152, 221, 202, 308, 131, 250, 299, 397, 303, 143, 201, 484, 497, 423, 269, 253, 442, 944, 845, 378, 231, 460, 420, 455, 538, 438

Offset

2,2

Comments

For definitions and more comments, see A238854 and A238850.

Conjecture: in any base n, the number of right-truncatable reversible primes is finite.

Links

Stanislav Sykora, Table of n, a(n) for n = 2..390

Stanislav Sykora, PARI/GP scripts for genetic threads, with code and comments

Example

In bases 10, 16, 100, and 256 (used as examples in the crossrefs) there are, respectively, 16, 40, 1552, and 35127 such numbers.

Prog

(PARI) See the link.

Crossrefs

Cf. Full in base 10: A238850, 16: A238851, 100: A238852, 256: A238853.

Cf. In base n: A238854 (largest), A238856 (maximum digits), A238857 (m-digit counts).

Cf. A007500, A023107, A024770, A237600, A237601, A237602.

Sequence in context: A348997 A354781 A097850 * A034854 A164982 A348996

Adjacent sequences: A238852 A238853 A238854 * A238856 A238857 A238858

Keyword

nonn,base

Author

Stanislav Sykora, Mar 07 2014

Status

approved