A098919 Least k such that k*M#(n) - 1 is prime where M#(n) is the product of the first n Mersenne primes.

2, 2, 2, 16, 2, 24, 8, 66, 6, 38, 44, 142, 116, 20, 460, 2974, 5774, 1110, 2520, 3422

Offset

1,1

Links

Table of n, a(n) for n=1..20.

Example

2*(2^2-1)*(2^3-1)*(2^5-1) - 1 = 1301, which is prime, so k(3)=2.

Crossrefs

Sequence in context: A025521 A305109 A068218 * A161748 A369011 A346079

Adjacent sequences: A098916 A098917 A098918 * A098920 A098921 A098922

Keyword

hard,more,nonn

Author

Pierre CAMI, Oct 17 2004

Extensions

a(15)-a(20) from Donovan Johnson, Mar 23 2008

Status

approved