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

KEYWORD

base,nonn

AUTHOR

Lucas H. Gabrielli, Aug 08 2019

STATUS

approved