

A157200


Numbers n such that n*(2n)^n1 is a prime.


0



2, 3, 6, 7, 12, 21, 113, 404, 735, 1944, 4973
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OFFSET

1,1


COMMENTS

Conjecture: there are infinite numbers of such kind of primes.
a(12) > 10000. [From Donovan Johnson, Aug 31 2010]


LINKS

Table of n, a(n) for n=1..11.


EXAMPLE

n=2, 2*(2*2)^21 = 31 is a prime number; n=3, 3^(2*3)^21 = 107 is a prime number; and so on


MATHEMATICA

Do[cp=n*(2*n)^n1; If[PrimeQ[cp], Print[n]], {n, 1, 2000}] This generates the listed first 10 elements.


PROG

(PARI) is(n)=ispseudoprime(n*(2*n)^n1) \\ Charles R Greathouse IV, Jun 17 2013


CROSSREFS

Sequence in context: A238590 A144120 A073712 * A255940 A167415 A018511
Adjacent sequences: A157197 A157198 A157199 * A157201 A157202 A157203


KEYWORD

hard,nice,nonn


AUTHOR

Lei Zhou, Feb 25 2009


EXTENSIONS

a(11) from Donovan Johnson, Aug 31 2010


STATUS

approved



