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A124477 Numbers n such that 24n+7 is a Mersenne prime (A000668). 26

%I

%S 0,1,5,341,5461,21845,89478485,96076792050570581,

%T 25790417485112089060398421,6760803201217223474649083762005,

%U 7089215977519551322153637654828504405

%N Numbers n such that 24n+7 is a Mersenne prime (A000668).

%C Note that 2^m - 1 can be expressed as 24*n+7 whenever m is an odd integer >= 3. - _Robert Israel_, Jul 08 2014

%H Michel Marcus, <a href="/A124477/b124477.txt">Table of n, a(n) for n = 1..18</a>

%p seq((numtheory:-mersenne([i+1])-7)/24, i=1..20); # _Robert Israel_, Jul 08 2014

%o (PARI) for(n=0, 1e20, k=0; if(ispseudoprime(24*n+7), while(2^k-1 < 24*n+7, k++); if(24*n+7==2^k-1, print1(n, ", ")))) \\ _Felix Fröhlich_, Jul 04 2014

%o (PARI) lista(nn) = {vmps = readvec("b000043.txt"); if (nn== 0, nn = #vmps); for (i=1, nn, mpi = 2^vmps[i]-8; if ((mpi % 24) == 0, print1(mpi/24, ", ")););} \\ _Michel Marcus_, Jul 05 2014

%Y Cf. A139480.

%K nonn

%O 1,3

%A _Artur Jasinski_, Dec 17 2006

%E a(11) corrected by _Michel Marcus_, Jul 05 2014

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Last modified February 19 10:34 EST 2019. Contains 320310 sequences. (Running on oeis4.)