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A007646 Numbers k such that k*4^k + 1 is prime.
(Formerly M2699)
7
1, 3, 7, 33, 67, 223, 663, 912, 1383, 3777, 3972, 10669, 48375 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 26 20:32 EDT 2022. Contains 354885 sequences. (Running on oeis4.)