A058775 Numbers n such that n * 2^(n/2) - 1 is prime.

2, 6, 8, 20, 54, 68, 468, 648, 1100, 1374, 14072, 17790, 20038, 27192, 42692

Offset

1,1

References

Posting to NMBRTHRY(AT)LISTSERV.NODAK.EDU by Mike Oakes Dec 30 2000 entitled "Gaussian analogues of the Cullen and Woodall primes."

Links

Table of n, a(n) for n=1..15.

Index entries for Gaussian integers and primes

Mathematica

Do[ If[ PrimeQ[n*2^(n/2) - 1], Print[n] ], {n, 1, 100000} ]
Select[Range[2, 43000, 2], PrimeQ[#*2^(#/2)-1]&] (* Harvey P. Dale, Dec 13 2018 *)

Prog

(PARI) is(n)=isprime(n*2^(n/2)-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A289095 A290160 A290213 * A103023 A341732 A111247

Adjacent sequences: A058772 A058773 A058774 * A058776 A058777 A058778

Keyword

nonn,easy

Author

Robert G. Wilson v, Jan 02 2001

Status

approved