A087091 Numbers k such that p = k^2 + k + 41 and p - 2 are twin primes.

1, 4, 10, 16, 19, 31, 34, 43, 55, 58, 61, 70, 73, 79, 85, 94, 100, 118, 148, 154, 160, 175, 196, 199, 211, 214, 223, 226, 229, 238, 253, 274, 313, 340, 424, 430, 469, 499, 508, 529, 538, 541, 550, 565, 640, 658, 673, 706, 724, 760, 763, 781

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

4 is in the sequence because 61 = 4^2 + 4 + 41 and 59 are twin primes.

Mathematica

Select[Range[10^3], And @@ PrimeQ[#^2 + # + {39, 41}] &] (* Amiram Eldar, Dec 27 2019 *)

Prog

(PARI) isok(n) = isprime(n^2+n+41) && isprime(n^2+n+39); \\ Michel Marcus, Oct 03 2013

Crossrefs

Cf. A007634, A087090.

Sequence in context: A310486 A310487 A310488 * A310489 A310490 A310491

Adjacent sequences: A087088 A087089 A087090 * A087092 A087093 A087094

Keyword

nonn

Author

Zak Seidov, Aug 08 2003

Status

approved