A110932 Numbers k such that 2*k^k + 1 is prime.

0, 1, 12, 18, 251, 82992

Offset: 0

Author

Ray G. Opao, Sep 25 2005

Keywords

• nonn
• hard
• more

Comments

As a "list of numbers such that ...", the sequence should have offset 1, but to preserve the validity of formulas referring to this sequence, the offset was set to 0 when the initial value a(0)=0 was added. - M. F. Hasler, Sep 02 2012

Crossrefs

Cf. A110931, A121270 (= primes in A014566), A088790, A160360, A160600.

The primes 2n^n+1, for k<4, n=a(k)<251, are listed at A216148(k) = A216147(a(k)). - M. F. Hasler, Sep 02 2012

Programs

Mathematica

Join[{0}, Select[Range[1000], PrimeQ[2*#^# + 1] &]] (* Robert Price, Mar 27 2019 *)

PARI

is_A110932(n)=ispseudoprime(n^n*2+1) \\ M. F. Hasler, Sep 02 2012

Extensions

a(5) from Serge Batalov, Apr 08 2018