A145479 Primes p such that (31+p)/2 is prime.

3, 7, 31, 43, 103, 127, 163, 223, 271, 283, 331, 367, 523, 631, 643, 727, 787, 811, 883, 967, 1051, 1063, 1123, 1171, 1231, 1291, 1423, 1447, 1471, 1483, 1543, 1627, 1723, 1783, 1951, 1987, 2011, 2143, 2203, 2311, 2371, 2467, 2551, 2731, 2767, 2887, 3067

Offset: 1

Author

Artur Jasinski, Oct 11 2008

Keywords

• nonn

Comments

All terms are congruent to 3 mod 4 and (with the exception of the first term) to 7 mod 12.

Links

• Ivan Neretin, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A092109, A145471, A145472, A145473, A145474, A145475, A145476, A145477, A145478, A145479, A155480.

Programs

Mathematica

aa = {}; k = 31; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}];aa
Select[Prime[Range[500]],PrimeQ[(31+#)/2]&] (* Harvey P. Dale, Feb 05 2012 *)

PARI

list(n)=my(t=1, p, i=1); while(i2&&isprime((31+p)/2),print1(p, ", "))) \\ Anders Hellström, Jan 23 2017