A200655 a(n)= least number k > a(n-1) such that k*(2^p-1)*(k*(2^p-1)+1)-1 is prime, where p = A000043(n) = Mersenne exponents.

1, 3, 5, 7, 8, 19, 20, 23, 96, 190, 312, 400, 434, 852, 980, 1063, 1208, 3960, 5464, 6694, 7178, 13118, 13680, 18803, 27445, 28541, 42031, 73209, 83873

Offset

1,2

Comments

a(n) is not so far from p

All certified primes using PFGW64 from primeform group

Links

Table of n, a(n) for n=1..29.

Crossrefs

Cf. A000043, A121370

Sequence in context: A081453 A352105 A345343 * A249439 A276693 A127050

Adjacent sequences: A200652 A200653 A200654 * A200656 A200657 A200658

Keyword

nonn

Author

Pierre CAMI, Nov 21 2011

Status

approved