A059327 a(n) is smallest safe prime (A005385) such that a(n) + 12*n is the next safe prime, i.e., x = (a(n) - 1)/2 and x + 6*n are closest Sophie Germain primes.

11, 23, 227, 179, 107, 1367, 263, 887, 2099, 719, 587, 8819, 3467, 1019, 10163, 27827, 1619, 7823, 27299, 2207, 44267, 3203, 7247, 5099, 11807, 45887, 18119, 15803, 79559, 13163, 40127, 42839, 20663, 79979, 17483, 53267, 47963, 33863

Offset: 1

Author

Labos Elemer, Jan 26 2001

Keywords

• nonn

Examples

			{11, 23, 227, 179, 107, ...} are the smallest safe primes such that {11+12, 23+24, 227+36, 179+48, 107+60, ...} = {23, 47, 263, 227, 167, ...} are their next safe primes to which the corresponding Sophie Germain primes are {11, 23, 131, 113, 83, ...} respectively.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A005384, A005385, A033299.

Programs

Mathematica

safeQ[p_] := PrimeQ[(p-1)/2]; max = 38; seq = Table[0, {max}]; c=0; p1 = p2 = 11; While[c < max, p2 = NextPrime[p2]; If[safeQ[p2], d = (p2 - p1)/12; If[d <= max && seq[[d]] == 0, c++; seq[[d]] = p1]; p1 = p2]]; seq (* Amiram Eldar, Jan 13 2020 *)

Extensions

Offset corrected by Amiram Eldar, Jan 13 2020