A007646 Numbers k such that k*4^k + 1 is prime. (Formerly M2699)

1, 3, 7, 33, 67, 223, 663, 912, 1383, 3777, 3972, 10669, 48375

Offset

1,2

References

H. Dubner, Generalized Cullen numbers, J. Rec. Math., 21 (No. 3, 1989), 190-191.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=1..13.

G. Loeh, Generalized Cullen primes

Prog

(PARI) is(n)=ispseudoprime(n*4^n+1) \\ Charles R Greathouse IV, Feb 17 2017

Crossrefs

Sequence in context: A089622 A241147 A143967 * A238314 A120566 A057480

Adjacent sequences: A007643 A007644 A007645 * A007647 A007648 A007649

Keyword

hard,nonn

Author

N. J. A. Sloane

Extensions

More terms from Robert G. Wilson v

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008

Status

approved