A080816 Triangle read by rows in which n-th row gives trajectory of n (omitting n itself) under the map k -> k+1 if k odd, k -> k/2 if k even.

1, 4, 2, 1, 2, 1, 6, 3, 4, 2, 1, 3, 4, 2, 1, 8, 4, 2, 1, 4, 2, 1, 10, 5, 6, 3, 4, 2, 1, 5, 6, 3, 4, 2, 1, 12, 6, 3, 4, 2, 1, 6, 3, 4, 2, 1, 14, 7, 8, 4, 2, 1, 7, 8, 4, 2, 1, 16, 8, 4, 2, 1, 8, 4, 2, 1, 18, 9, 10, 5, 6, 3, 4, 2, 1, 9, 10, 5, 6, 3, 4, 2, 1, 20, 10, 5, 6, 3, 4, 2, 1, 10, 5, 6, 3, 4, 2, 1, 22

Offset: 1

Author

Cino Hilliard, Mar 26 2003

Keywords

• easy
• nonn
• tabf

Examples

			7 -> 8 -> 4 -> 2 -> 1, so the 7th row is 8,4,2,1.
		

Links

• Cino Hilliard, The x+1 conjecture

Crossrefs

Cf. A061313 (row lengths).

Programs

Mathematica

Table[Rest[NestWhileList[If[OddQ[#],#+1,#/2]&,n,#>1&]],{n,30}] //Flatten (* Harvey P. Dale, Dec 04 2016 *)

PARI

xnp1(n,p) = { print1(1" "); for(x=1,n, p1 = x; while(p1>1, if(p1%2==0,p1/=2,p1 = p1*p+1;); print1(p1" ") ) ) }