A227916 Primes that remain prime when the leftmost digit is removed.

13, 17, 23, 37, 43, 47, 53, 67, 73, 83, 97, 103, 107, 113, 131, 137, 167, 173, 179, 197, 211, 223, 229, 241, 271, 283, 307, 311, 313, 317, 331, 337, 347, 353, 359, 367, 373, 379, 383, 389, 397, 419, 431, 443, 461, 467, 479, 503, 523, 541, 547, 571, 607, 613, 617

Offset

1,1

Links

K. D. Bajpai, Table of n, a(n) for n = 1..10000

Example

a(11)= 97 which is prime. Removing the leftmost digit gives 7, also prime.
a(28)= 311 which is prime. Removing the leftmost digit gives 11, also prime.

Maple

KD:= proc() local a, b, c, d; a:=ithprime(n); b:=length(a); c:=floor(a/(10^(b-1))); d:=a-c*(10^(b-1)); if isprime(d) then return(a):fi; end:seq(KD(), n=1..5000);

Crossrefs

Cf. A000040 (prime numbers), A024785 (left-truncatable primes).

Cf. A137812 (left- or right-truncatable primes).

Cf. A227919 (primes which remain prime when rightmost digit is removed).

Sequence in context: A022893 A211490 A038680 * A158072 A277689 A240894

Adjacent sequences: A227913 A227914 A227915 * A227917 A227918 A227919

Keyword

nonn,base

Author

K. D. Bajpai, Oct 13 2013

Status

approved