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A057224
Numbers k such that (Product of first k Mersenne prime exponents) + 1 is prime.
1
1, 2, 3, 4, 5, 6, 13, 17
OFFSET
1,2
COMMENTS
a(9) > 48, if it exists. - Amiram Eldar, Oct 19 2024
MATHEMATICA
Position[FoldList[Times, MersennePrimeExponent[Range[48]]] + 1, _?PrimeQ] // Flatten (* Amiram Eldar, Oct 19 2024 *)
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
Sequence in context: A072564 A223938 A222194 * A153695 A300857 A255261
KEYWORD
nonn,more
AUTHOR
G. L. Honaker, Jr., Sep 18 2000
STATUS
approved