A235484 Square numbers n such that n^2 - n - 1 is prime.

4, 9, 16, 25, 36, 49, 121, 196, 289, 324, 361, 529, 625, 729, 1024, 1296, 1681, 1849, 2916, 3600, 4225, 4761, 5184, 5929, 6400, 6724, 6889, 7569, 7744, 8464, 8649, 9604, 12100, 13689, 14641, 14884, 15876, 16129, 18225, 18496, 19044, 22201, 22500, 24025, 24649, 25281, 28224

Offset: 1

Author

Zak Seidov, Apr 13 2014

Keywords

• nonn

Comments

Or, squares in A002328: a(1) = 4 = A002328(2), a(2) = 9 = A002328(6), a(1) = 16 = A002328(11).

The corresponding primes, 11, 71, 239, 599, 1259, 2351, 14519, 38219, 83231, 104651, 129959, 279311, 389999, 530711, 1047551, 1678319, are a subsequence of A002327.

Crossrefs

Intersection of A002328 and A000290. Cf. A002327.

Programs

Mathematica

Select[Table[n^2, {n, 100}], PrimeQ[#^2 - # - 1] &]

PARI

list(lim)=my(v=List()); for(n=2,sqrtint(lim\1), if(isprime(n^2-n-1), listput(v,n))); Vec(v) \\ Charles R Greathouse IV, Jun 13 2017