A007646 Numbers k such that k*4^k + 1 is prime.

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

Offset: 1

Author

N. J. A. Sloane

Keywords

• hard
• nonn

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

• G. Loeh, Generalized Cullen primes

Programs

PARI

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

Extensions

More terms from Robert G. Wilson v

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