A136243 Numbers k in A008864 such that k^2 - k - 1 is prime.

3, 4, 6, 12, 14, 20, 32, 42, 54, 60, 84, 90, 102, 104, 132, 150, 164, 182, 192, 194, 200, 234, 242, 264, 282, 332, 350, 374, 402, 420, 432, 434, 450, 462, 464, 500, 542, 570, 572, 660, 674, 684, 692, 710, 740, 744, 762, 770, 810, 864, 882, 942, 1014, 1040

Offset: 1

Author

Lekraj Beedassy, Dec 24 2007

Keywords

• nonn

Comments

See A053185 for the primes associated with a(n).

Crossrefs

Cf. A008864, A053184, A136242.

Programs

PARI

isok(k) = isprime(k-1) && isprime(k^2-k-1); \\ Michel Marcus, Dec 19 2022

Formula

a(n) = A053184(n) + 1.

Extensions

a(20)=194 inserted by Georg Fischer, Dec 18 2022