

A245743


Primes p such that p  d is also prime, where d is the largest digit of p.


6



41, 163, 181, 263, 401, 443, 463, 487, 563, 613, 653, 1021, 1381, 1433, 1613, 1663, 1831, 2141, 2243, 2281, 2441, 2663, 2851, 2887, 3041, 3463, 3613, 3623, 3643, 4133, 4363, 4463, 4603, 4643, 4663, 4801, 5281, 5563, 5581, 5653, 5821, 5851, 5857, 6043, 6053
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OFFSET

1,1


COMMENTS

The least significant digit of a(n) is either 1, 3 or 7.  Colin Barker, Aug 03 2014
The largest digit of a(n) is 2, 4, 6 or 8.  Robert Israel, Aug 03 2014


LINKS

Jens Kruse Andersen, Table of n, a(n) for n = 1..10000


EXAMPLE

263 is in the sequence because 263  6 = 257, which is prime.


MAPLE

filter:= n > isprime(n) and isprime(n  max(convert(n, base, 10))):
select(filter, [$1..10^5]); # Robert Israel, Aug 03 2014


PROG

(PARI) select(p>isprime(pvecsort(digits(p), , 4)[1]), primes(2000))
(MAGMA) [p: p in PrimesUpTo(7000)  IsPrime(pd) where d is Max(Intseq(p))]; // Bruno Berselli, Jul 31 2014


CROSSREFS

Cf. A245742, A245744, A245745.
Sequence in context: A105100 A141988 A158602 * A142839 A142912 A158626
Adjacent sequences: A245740 A245741 A245742 * A245744 A245745 A245746


KEYWORD

nonn,base


AUTHOR

Colin Barker, Jul 31 2014


STATUS

approved



