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

%I A245744 #21 Sep 08 2022 08:46:09
%S A245744 29,67,89,227,239,269,457,487,499,607,677,827,2027,2087,2237,2267,
%T A245744 2309,2339,2549,2657,2687,2729,2789,2969,2999,3257,3299,3329,3527,
%U A245744 3929,4229,4259,4447,4789,4969,4999,5279,5479,5647,6067,6269,6299,6469,6547,6827
%N A245744 Primes p such that p + d is also prime, where d is the smallest nonzero digit of p.
%C A245744 The least significant digit of a(n) is either 7 or 9. - _Colin Barker_, Aug 03 2014
%C A245744 The smallest nonzero digit of a(n) is 2, 4, 6 or 8. - _Colin Barker_, Aug 04 2014
%H A245744 Jens Kruse Andersen, <a href="/A245744/b245744.txt">Table of n, a(n) for n = 1..10000</a>
%e A245744 607 is in the sequence because 607 + 6 = 613, which is prime.
%o A245744 (PARI) select(p->v=vecsort(digits(p),,8); isprime(p+v[1+!v[1]]), primes(2000))
%o A245744 (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
%Y A245744 Cf. A245742, A245743, A245745.
%K A245744 nonn,base
%O A245744 1,1
%A A245744 _Colin Barker_, Jul 31 2014