1,1
Primes of the form 2*A005329(k)+1.
Table of n, a(n) for n=1..9.
For n=4, 2*(2^1 - 1)*(2^2 - 1)*(2^3 -1)*(2^4 - 1) + 1 = 2*1*3*7*15 + 1 = 631
Sequence in context: A181729 A162455 A143684 * A050639 A280717 A100837
Adjacent sequences: A156890 A156891 A156892 * A156894 A156895 A156896
nonn
J. M. Bergot, Feb 17 2009
Definition and terms corrected by R. J. Mathar, Jul 10 2011
approved
