Number of steps to reach a prime under "replace n with concatenation of its prime factors", or -1 if no prime is ever reached.

A037273

Number of steps to reach a prime under "replace n with concatenation of its prime factors", or -1 if no prime is ever reached.

Terms

    a(0) =-1a(1) =0a(2) =0a(3) =2a(4) =0a(5) =1a(6) =0a(7) =13a(8) =2a(9) =4a(10) =0a(11) =1a(12) =0a(13) =5a(14) =4a(15) =4a(16) =0a(17) =1a(18) =0a(19) =15a(20) =1a(21) =1a(22) =0a(23) =2a(24) =3a(25) =4a(26) =4a(27) =1a(28) =0a(29) =2

External references