A309572 Number of primes of which all substrings in base n are primes.

0, 1, 3, 5, 5, 7, 19, 7, 9, 6, 25, 11, 22, 16, 18, 12, 54, 12, 48, 18, 33, 13, 103, 16, 27, 20, 50, 13, 161, 14, 66, 27, 47, 19, 109, 18, 67, 22, 70, 15, 226, 22, 82, 33, 67, 24, 261, 26, 137, 29, 89, 23, 273, 29, 102, 31, 82, 24, 546, 26, 119, 37, 110, 29

Offset

2,3

Links

Rémy Sigrist, Table of n, a(n) for n = 2..2500 (first 199 terms from Lucas H. Gabrielli)

Rémy Sigrist, Colored logarithmic scatterplot of the first 2500 terms

Rémy Sigrist, PARI program for A309572

Example

For base 10, there are 9 primes whose substrings are also primes: 2, 3, 5, 7, 23, 37, 53, 73, and 373, thus a(10) = 9.

Prog

(PARI) See Links section.

Crossrefs

Cf. A245277.

Sequence in context: A090941 A090917 A226540 * A366679 A296107 A158331

Adjacent sequences: A309569 A309570 A309571 * A309573 A309574 A309575

Keyword

base,nonn

Author

Lucas H. Gabrielli, Aug 08 2019

Status

approved