A238856 Number of digits of the largest right-truncatable reversible prime in base n.

0, 3, 3, 4, 3, 4, 5, 4, 4, 6, 4, 6, 6, 6, 6, 5, 4, 7, 6, 7, 5, 6, 5, 8, 6, 6, 6, 6, 7, 7, 6, 6, 8, 6, 8, 7, 8, 8, 7, 8, 7, 8, 8, 8, 8, 7, 7, 9, 9, 8, 7, 8, 10, 10, 9, 8, 6, 9, 8, 7, 9, 9, 9, 9, 11, 8, 7, 9, 10, 9, 10, 9, 9, 11, 10, 10, 9, 9, 8, 9, 9, 8, 10, 10, 10, 9, 9, 9, 10, 11

Offset

2,2

Comments

For definitions and more comments, see A238854 and A238850. A weak conjecture: this sequence might be bounded.

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

a(16) = 6 because the largest truncatable reversible prime in base 16 has 6 hexadecimal digits (see A238851).

Prog

(PARI) See the link.

Crossrefs

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

Cf. In base n: A238854 (largest), A238855 (totals), A238857 (m-digit counts).

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

Sequence in context: A216190 A267592 A243341 * A096139 A175928 A161357

Adjacent sequences: A238853 A238854 A238855 * A238857 A238858 A238859

Keyword

nonn,base,hard

Author

Stanislav Sykora, Mar 13 2014

Status

approved