a(1) = 1. For n>1, let x = a(n-1)+1; then a(n) is the first prime in the sequence 2*x-1, 2*x-3, 4*x-1, 4*x-3, 8*x-1, 8*x-3, ..., (2^k)*x-1, (2^k)*x-3, ...

A083201

a(1) = 1. For n>1, let x = a(n-1)+1; then a(n) is the first prime in the sequence 2*x-1, 2*x-3, 4*x-1, 4*x-3, 8*x-1, 8*x-3, ..., (2^k)*x-1, (2^k)*x-3, ...

Terms

    a(0) =1a(1) =3a(2) =7a(3) =13a(4) =53a(5) =107a(6) =431a(7) =863a(8) =6911a(9) =27647a(10) =442367a(11) =7247757311

External references