a(1) = 4; a(n) is least semiprime > a(n-1)^2.A118909a(1) = 4; a(n) is least semiprime > a(n-1)^2.Terms a(0) =4a(1) =21a(2) =445a(3) =198026a(4) =39214296677External referencesoeis: A118909