1,1

Table of n, a(n) for n=1..19.

K. Bonath, First SG

Example for n=7: a(7)=99 because 99*2^7-1 and 99*2^8-1 is the first occurance for n=7 as a Sophie Germain prime pair.

Cf. A076806 (minimal odd k such that k*2^n-1 and k*2^n+1 are twin primes).

Sequence in context: A327149 A173424 A143081 * A112811 A197272 A306773

Adjacent sequences: A179655 A179656 A179657 * A179659 A179660 A179661

nonn

Karsten Bonath, Jul 23 2010

approved