a(1) = 2, a(2n) = smallest prime of the form k*a(2n-1) -1, k >1, a(2n+1) = smallest prime of the form r*a(2n)+1, r >1.

A085872

a(1) = 2, a(2n) = smallest prime of the form k*a(2n-1) -1, k >1, a(2n+1) = smallest prime of the form r*a(2n)+1, r >1.