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A098919
Least k such that k*M#(n) - 1 is prime where M#(n) is the product of the first n Mersenne primes.
0
2, 2, 2, 16, 2, 24, 8, 66, 6, 38, 44, 142, 116, 20, 460, 2974, 5774, 1110, 2520, 3422
OFFSET
1,1
EXAMPLE
2*(2^2-1)*(2^3-1)*(2^5-1) - 1 = 1301, which is prime, so k(3)=2.
CROSSREFS
Sequence in context: A305109 A372418 A068218 * A161748 A369011 A346079
KEYWORD
hard,more,nonn
AUTHOR
Pierre CAMI, Oct 17 2004
EXTENSIONS
a(15)-a(20) from Donovan Johnson, Mar 23 2008
STATUS
approved