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

1,1

Links

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

Example

{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.

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 *)

Crossrefs

Cf. A005384, A005385, A033299.

Sequence in context: A261352 A018979 A181147 * A042005 A153318 A005485

Adjacent sequences: A059324 A059325 A059326 * A059328 A059329 A059330

Keyword

nonn

Author

Labos Elemer, Jan 26 2001

Extensions

Offset corrected by Amiram Eldar, Jan 13 2020

Status

approved