Becomes prime or 4 after exactly 7 iterations of f(x) = sum of prime factors of x.

Terms

a(0) =393a(1) =422a(2) =614a(3) =674a(4) =692a(5) =886a(6) =889a(7) =934a(8) =993a(9) =1006a(10) =1270a(11) =1285a(12) =1502a(13) =1522a(14) =1524a(15) =1542a(16) =1726a(17) =1822a(18) =2018a(19) =2217a(20) =2326a(21) =2386a(22) =2402a(23) =2474a(24) =2545a(25) =2654a(26) =2733a(27) =2734a(28) =2761a(29) =2858