1,1

Table of n, a(n) for n=1..55.

a(1)=1 because 1*2+1=3=prime and 1*6+1=7=prime.

a(1)=3 because 3*2+1=7 and 3*6+1=19 are primes congruent to 1 (mod 6). [From R. J. Mathar, Apr 16 2010]

Cf. A002476, A065091.

Sequence in context: A078318 A193433 A074370 * A088339 A064400 A117863

Adjacent sequences: A174098 A174099 A174100 * A174102 A174103 A174104

nonn

Juri-Stepan Gerasimov, Mar 07 2010

More terms from R. J. Mathar, Apr 16 2010

approved