1,1

First primes p such that (2k+1)p-2k k=1..7 are

25153801,507079861,610817971,942962791,1040241511,1223511871,1797884761.

First primes p such that (2k+1)p-2k k=1..8 are

4747505071,10817047081,21071155561,41279978041,44304317821,

49710893611,58845917971,79925475841,96466884361,106120099471,107001847261.

Table of n, a(n) for n=1..8.

Cf. A088878 Prime numbers p such that 3p-2 is a prime.

Sequence in context: A273043 A066142 A232459 * A248859 A171543 A079073

Adjacent sequences: A175563 A175564 A175565 * A175567 A175568 A175569

nonn

Zak Seidov, Jul 11 2010

approved