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
Examples
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.
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
Crossrefs
Cf. A245277.
Programs
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PARI
See Links section.