If a(n) is prime then a(n+1) = a(n)^2+9, otherwise a(n+1) = floor(a(n)/2), with a(1) = 2.

A307655

If a(n) is prime then a(n+1) = a(n)^2+9, otherwise a(n+1) = floor(a(n)/2), with a(1) = 2.