A057225 Numbers k such that (Product of first k Mersenne prime exponents) - 1 is prime.

2, 3, 5, 9, 13, 27

Offset

1,1

Comments

a(7) > 48, if it exists. - Amiram Eldar, Oct 19 2024

Links

Table of n, a(n) for n=1..6.

Mathematica

Position[FoldList[Times, MersennePrimeExponent[Range[30]]]-1, _?PrimeQ]//Flatten (* Harvey P. Dale, Oct 01 2023 *)

Prog

(PARI) lista(v) = {for (n=1, #v, if (isprime(prod(k=1, n, v[k]) - 1), print1(n, ", ")); ); } \\ with v=A000043. Michel Marcus, Jan 07 2014

Crossrefs

Cf. A000043, A057224.

Sequence in context: A175125 A171925 A186946 * A309289 A220315 A070819

Adjacent sequences: A057222 A057223 A057224 * A057226 A057227 A057228

Keyword

nonn,more

Author

G. L. Honaker, Jr., Sep 18 2000

Status

approved