A007646 - OEIS

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

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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

PROG

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

CROSSREFS

KEYWORD

hard,nonn

AUTHOR

EXTENSIONS

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

STATUS

approved