Least number which becomes prime or 4 after exactly n iterations of f(x) = sum of prime factors of x.

A048133

Least number which becomes prime or 4 after exactly n iterations of f(x) = sum of prime factors of x.

Terms

    a(0) =2a(1) =6a(2) =8a(3) =14a(4) =26a(5) =62a(6) =134a(7) =393a(8) =1257a(9) =4659a(10) =9314a(11) =27933a(12) =167073a(13) =334142a(14) =4677862a(15) =14033577a(16) =56134292a(17) =2133102298a(18) =11788191218a(19) =52541651594a(20) =536226160966

External references