a(1) = a(2) = 2; a(n) = a(n-1) + gpf(a(n-2)), where gpf is greatest prime factor.

Terms

a(0) =2a(1) =2a(2) =4a(3) =6a(4) =8a(5) =11a(6) =13a(7) =24a(8) =37a(9) =40a(10) =77a(11) =82a(12) =93a(13) =134a(14) =165a(15) =232a(16) =243a(17) =272a(18) =275a(19) =292a(20) =303a(21) =376a(22) =477a(23) =524a(24) =577a(25) =708a(26) =1285a(27) =1344a(28) =1601a(29) =1608