A087255 Number of different initial values for 3x+1 trajectories of which the largest term appearing during the iteration equals n.

1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 12, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 3, 0, 0, 0, 1, 0

Offset: 1

Author

Labos Elemer, Sep 08 2003

Keywords

• nonn

Examples

			a(2k+1)=a(4k+2)=a(16k+12)=0 because larger values appear in iteration: 6k+4, 6k+4, and 18k+16, respectively. Exception: a(1)=a(2)=1.
Some outstanding cases: a(9232)=1579, a(13120)=75.
		

Links

• Jon E. Schoenfield, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A025586, A087251-A087254.

Extensions

Edited by Jon E. Schoenfield, Dec 01 2013