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A098818
Smallest k such that k*Mersenne_prime(n)^2 -1 (or k*A000668(n)^2 -1) is prime.
0
2, 2, 8, 2, 12, 2, 2, 98, 38, 122, 126, 678, 440, 1040, 776, 1398, 2714, 3362, 650, 8910, 22010, 11172, 1422, 5274, 33944, 4508, 12614, 202298, 275466
OFFSET
1,1
EXAMPLE
2*((2^2-1)^2)-1=17 prime so a(1)=2.
CROSSREFS
Sequence in context: A174354 A011147 A273168 * A092694 A098984 A088560
KEYWORD
more,nonn
AUTHOR
Pierre CAMI, Oct 08 2004
EXTENSIONS
a(19)-a(22) from Donovan Johnson, Mar 23 2008
a(23)-a(29) from Pierre CAMI, Feb 15 2014
STATUS
approved