1,1

a(n) = A000668(2*n - 1).

a(3) = 8191 because the (2*3-1=5)th Mersenne prime is 8191.

Cf. A000668, A134722.

Adjacent sequences: A134718 A134719 A134720 this_sequence A134722 A134723 A134724

Sequence in context: A048562 A022499 A129209 this_sequence A002707 A144964 A118913

easy,nonn

Omar E. Pol (info(AT)polprimos.com), Nov 11 2007