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A098818 Smallest k such that k*Mersenne_prime(n)^2 -1 (or k*A000668(n)^2 -1) is prime. 0

%I

%S 2,2,8,2,12,2,2,98,38,122,126,678,440,1040,776,1398,2714,3362,650,

%T 8910,22010,11172,1422,5274,33944,4508,12614,202298,275466

%N Smallest k such that k*Mersenne_prime(n)^2 -1 (or k*A000668(n)^2 -1) is prime.

%e 2*((2^2-1)^2)-1=17 prime so a(1)=2.

%Y Cf. A000668

%K more,nonn

%O 1,1

%A _Pierre CAMI_, Oct 08 2004

%E a(19)-a(22) from _Donovan Johnson_, Mar 23 2008

%E a(23)-a(29) from _Pierre CAMI_, Feb 15 2014

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Last modified May 22 18:53 EDT 2019. Contains 323481 sequences. (Running on oeis4.)