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A227916 Primes that remain prime when the leftmost digit is removed. 9
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 16 05:35 EDT 2019. Contains 328044 sequences. (Running on oeis4.)