A050986 Number of n-digit right-truncatable primes.

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

Offset

1,1

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

Table of n, a(n) for n=1..9.

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

Prog

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

Crossrefs

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

Sequence in context: A141560 A071864 A312987 * A284956 A261445 A034259

Adjacent sequences: A050983 A050984 A050985 * A050987 A050988 A050989

Keyword

base,nonn,easy,fini,full

Author

Eric W. Weisstein

Extensions

Edited by Ray Chandler, Mar 13 2007

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

Status

approved