

A156585


Numbers such that (2^(n^2)1)/(2^n1) is prime.


3




OFFSET

1,1


COMMENTS

It is easy to see that all terms of this sequence must be prime; this motivates the definition of A051156(n) = (2^prime(n)^21)/(2^prime(n)1).
No further terms up to n=1999.  Andreas Höglund, Apr 06 2018


LINKS

Table of n, a(n) for n=1..4.


MATHEMATICA

Select[Prime[Range[17]], PrimeQ[Cyclotomic[#^2, 2]] &] (* Arkadiusz Wesolowski, May 13 2012 *)


PROG

(PARI) for/*prime*/( n=1, 99, is/*pseudo*/prime( (2^n^21)/(2^n1) ) & print1(n, ", "))


CROSSREFS

Cf. A051156.
Sequence in context: A253574 A238399 A159611 * A299923 A337189 A087358
Adjacent sequences: A156582 A156583 A156584 * A156586 A156587 A156588


KEYWORD

hard,more,nonn


AUTHOR

M. F. Hasler, Feb 10 2009


STATUS

approved



