Numbers n such that h(n) = 2 h(n-1) where h(n) is the length of the sequence {n, f(n), f(f(n)), ...., 1} in the Collatz (or 3x + 1) problem. (The earliest "1" is meant.)

A078419

Numbers n such that h(n) = 2 h(n-1) where h(n) is the length of the sequence {n, f(n), f(f(n)), ...., 1} in the Collatz (or 3x + 1) problem. (The earliest "1" is meant.)

Terms

    a(0) =2a(1) =5a(2) =22a(3) =495a(4) =559a(5) =2972a(6) =3092a(7) =3124a(8) =3147a(9) =3153a(10) =3184a(11) =3367a(12) =3711a(13) =3748a(14) =3857a(15) =3921a(16) =3982a(17) =4450a(18) =4767a(19) =17019a(20) =17708a(21) =17769a(22) =17771a(23) =17782a(24) =17796a(25) =17825a(26) =17835a(27) =17857a(28) =17863a(29) =17892

External references