1,1

a(2)=20 because A109217(20) = 1101111011111101111111 is prime.

Cf. A000037, A109217.

Sequence in context: A115280 A081849 A022129 this_sequence A053748 A075358 A002461

Adjacent sequences: A109215 A109216 A109217 this_sequence A109219 A109220 A109221

more,nonn

Jason Earls (zevi_35711(AT)yahoo.com), Jun 22 2005