A238857 Array read by rows: row n lists total number of m-digit right-truncatable reversible primes in base n.

0, 1, 1, 1, 0, 2, 1, 1, 0, 2, 4, 4, 2, 0, 3, 1, 1, 0, 3, 5, 3, 1, 0, 4, 7, 7, 5, 1, 0, 4, 5, 5, 3, 0, 4, 5, 6, 1, 0, 4, 8, 7, 9, 4, 1, 0, 5, 5, 7, 5, 0, 5, 10, 8, 4, 1, 1, 0, 6, 11, 17, 12, 3, 1, 0, 6, 11, 13, 6, 2, 1, 0, 6, 9, 11, 9, 4, 1, 0, 6, 13, 12, 7, 1, 0, 7, 9, 7, 1, 0

Offset

2,6

Comments

For definitions and more comments, see A238854 and A238850.

This is an irregular table with one line for every base, starting at 2, while the columns correspond to the number of digits (1,2,3,...). Each row terminates with a zero (in any given base there appears to be a finite number of instances).

Links

Stanislav Sykora, Table of n, a(n) for n = 2..5071

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

Example

These are the first rows of the table:
   2: 0,
   3: 1, 1, 1, 0,
   4: 2, 1, 1, 0,
   5: 2, 4, 4, 2, 0,
   6: 3, 1, 1, 0,
   7: 3, 5, 3, 1, 0,
   8: 4, 7, 7, 5, 1, 0,
   9: 4, 5, 5, 3, 0,
  10: 4, 5, 6, 1, 0,
  ...
Hence, there are 6 right truncatable reversible primes with 3 digits in base 10 (see A238850).

Prog

(PARI) See the link.

Crossrefs

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

In base n: A238854 (largest), A238855 (totals), A238856 (maximum digits).

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

Sequence in context: A227425 A333213 A301636 * A253587 A110962 A065715

Adjacent sequences: A238854 A238855 A238856 * A238858 A238859 A238860

Keyword

nonn,tabf,base

Author

Stanislav Sykora, Mar 13 2014

Status

approved