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 A124477 Numbers k such that 24k+7 is a Mersenne prime (A000668). 26
 0, 1, 5, 341, 5461, 21845, 89478485, 96076792050570581, 25790417485112089060398421, 6760803201217223474649083762005, 7089215977519551322153637654828504405 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Note that 2^m - 1 can be expressed as 24*k+7 whenever m is an odd integer >= 3. - Robert Israel, Jul 08 2014 LINKS Michel Marcus, Table of n, a(n) for n = 1..18 FORMULA a(n) = (2^A000043(n+1)-8)/24. - Jeppe Stig Nielsen, Sep 17 2020 MAPLE seq((numtheory:-mersenne([i+1])-7)/24, i=1..20); # Robert Israel, Jul 08 2014 PROG (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 FrÃ¶hlich, Jul 04 2014 (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 CROSSREFS Cf. A000043, A000668, A139480. Sequence in context: A200002 A265921 A203684 * A059839 A300388 A269556 Adjacent sequences:  A124474 A124475 A124476 * A124478 A124479 A124480 KEYWORD nonn AUTHOR Artur Jasinski, Dec 17 2006 EXTENSIONS a(11) corrected by Michel Marcus, Jul 05 2014 STATUS approved

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Last modified August 19 18:30 EDT 2022. Contains 356229 sequences. (Running on oeis4.)