A050986 Number of n-digit right-truncatable primes.

4, 9, 14, 16, 15, 12, 8, 5, 0

Offset: 1

Author

Eric W. Weisstein

Keywords

• base
• nonn
• easy
• fini
• full

Comments

Right-truncatable means that the integer part of successive divisions by 10 always yields primes (or zero). - M. F. Hasler, Nov 07 2018

Links

• Jens Kruse Andersen, Right-truncatable primes
• I. O. Angell and H. J. Godwin, On Truncatable Primes, Math. Comput. 31, 265-267, 1977.
• Eric Weisstein's World of Mathematics, Truncatable Prime.
• Index entries for sequences related to truncatable primes
• Index entries for sequences related to numbers of primes in various ranges

Crossrefs

Cf. A033664, A024785, A032437, A020994, A024770, A052023, A052024, A052025, A050987.

Programs

PARI

A050986=vector(9, n, #p=concat(apply(t->primes([t, t+1]*10), if(n>1, p)))) \\ M. F. Hasler, Nov 07 2018

Extensions

Edited by Ray Chandler, Mar 13 2007

a(9) = 0 added by M. F. Hasler, Nov 07 2018