A213916 Sum of all odd numbers in Collatz (3x+1) trajectory of n.

1, 1, 9, 1, 6, 9, 54, 1, 63, 6, 47, 9, 19, 54, 132, 1, 36, 63, 95, 6, 22, 47, 117, 9, 120, 19, 20262, 54, 76, 132, 20194, 1, 153, 36, 94, 63, 91, 95, 450, 6, 20235, 22, 248, 47, 81, 117, 20163, 9, 140, 120, 204, 19, 59, 20262, 20426, 54, 305, 76, 411, 132, 178

Offset: 1

Author

Jayanta Basu, Mar 05 2013

Keywords

• nonn

Examples

			a(5)=6 since Collatz trajectory of 5 is 5,16,8,4,2,1.
		

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A033493, A213909.

Programs

Mathematica

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Table[Total[Select[Collatz[n], OddQ]], {n, 100}] (* T. D. Noe, Mar 05 2013 *)

Formula

a(n) = A033493(n) - A213909(n).