a(n) = least k such that 2ik + 1 is prime for all 1 <= i <= n.

A071576

a(n) = least k such that 2ik + 1 is prime for all 1 <= i <= n.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =165a(4) =5415a(5) =12705a(6) =256410a(7) =256410a(8) =6480303060a(9) =217245863835a(10) =946622690475

External references