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A249384 Smallest odd prime number Q such that Q*2^P+1 is also prime, where P is a Mersenne prime exponent A000043(n). 2

%I #10 Nov 21 2014 21:29:00

%S 3,5,3,5,5,53,11,239,53,191,1229,5,233,347,1367,9767,2063,89,14009,

%T 3329,19991,50849,2711,337871,46301,2543,413093,1157111,615161,

%U 1138649,3778427

%N Smallest odd prime number Q such that Q*2^P+1 is also prime, where P is a Mersenne prime exponent A000043(n).

%o (PARI) lista(nn) = {vmp = readvec("b000043.txt"); for (n=1, nn, k=2; while(!isprime(prime(k)*2^vmp[n]+1), k++); print1(prime(k), ", "););} \\ _Michel Marcus_, Oct 27 2014

%Y Cf. A000043, A249382, A249383.

%K nonn,more

%O 1,1

%A _Pierre CAMI_, Oct 27 2014

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Last modified September 9 15:40 EDT 2024. Contains 375765 sequences. (Running on oeis4.)