2-multiplicative persistence: number of iterations of "multiply 2nd powers of digits" needed to reach 0 or 1.

A031348

2-multiplicative persistence: number of iterations of "multiply 2nd powers of digits" needed to reach 0 or 1.

Terms

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

External references