A329477 a(n) is the number of iterations needed to reach 1 starting at n and using the map k -> (k/2 if k is even, otherwise k + (largest partition number < k)). Set a(n) = -1 if the trajectory never reaches 1.

0, 1, 5, 2, 4, 6, 8, 3, 5, 5, 7, 7, 9, 9, 11, 4, 6, 6, 8, 6, 8, 8, 27, 8, 14, 10, 14, 10, 31, 12, 41, 5, 33, 7, 39, 7, 16, 9, 20, 7, 22, 9, 29, 9, 26, 28, 13, 9, 13, 15, 30, 11, 32, 15, 28, 11, 17, 32, 19, 13, 40, 42, 32, 6, 38, 34, 15, 8, 19, 40, 21, 8, 21

Offset

1,3

Links

Table of n, a(n) for n=1..73.

Example

The trajectory of 15 is [15, 26, 13, 24, 12, 6, 3, 5, 8, 4, 2, 1], taking 11 steps to reach 11. So a(15) = 11.

Crossrefs

Cf. A000041.

Sequence in context: A188739 A308171 A265287 * A257701 A202494 A112597

Adjacent sequences: A329474 A329475 A329476 * A329478 A329479 A329480

Keyword

nonn

Author

Ali Sada, Nov 13 2019

Status

approved