A143385 Least a(n) such that M(n)*(M(n)+a(n))-1 and M(n)*(M(n)+a(n))+1 are twin primes with M(i)=i-th Mersenne prime.

1, 53, 11, 17, 317, 89, 737, 2543, 1247, 6209, 15107, 33119, 60611, 671063, 2648057

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Example

(2^2-1)*(2^2-1+1)-1=11 prime, 11 and 13 twin primes, 2^2-1=M(1) so a(1)=1

Crossrefs

Cf. A139426.

Sequence in context: A078681 A143294 A143428 * A231426 A298061 A297984

Adjacent sequences: A143382 A143383 A143384 * A143386 A143387 A143388

Keyword

hard,more,nonn

Author

Pierre CAMI, Aug 11 2008

Status

approved