A245744 Primes p such that p + d is also prime, where d is the smallest nonzero digit of p.

29, 67, 89, 227, 239, 269, 457, 487, 499, 607, 677, 827, 2027, 2087, 2237, 2267, 2309, 2339, 2549, 2657, 2687, 2729, 2789, 2969, 2999, 3257, 3299, 3329, 3527, 3929, 4229, 4259, 4447, 4789, 4969, 4999, 5279, 5479, 5647, 6067, 6269, 6299, 6469, 6547, 6827

Offset

1,1

Comments

The least significant digit of a(n) is either 7 or 9. - Colin Barker, Aug 03 2014

The smallest nonzero digit of a(n) is 2, 4, 6 or 8. - Colin Barker, Aug 04 2014

Links

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

Example

607 is in the sequence because 607 + 6 = 613, which is prime.

Prog

(PARI) select(p->v=vecsort(digits(p), , 8); isprime(p+v[1+!v[1]]), primes(2000))
(Magma) [p: p in PrimesUpTo(7000) | IsPrime(p+d) where d is [i: i in Set(Intseq(p)) | not IsZero(i)][1]]; // Bruno Berselli, Jul 31 2014

Crossrefs

Cf. A245742, A245743, A245745.

Sequence in context: A201022 A367151 A118481 * A141875 A294615 A182332

Adjacent sequences: A245741 A245742 A245743 * A245745 A245746 A245747

Keyword

nonn,base

Author

Colin Barker, Jul 31 2014

Status

approved