A213909 Sum of all even numbers in Collatz (3x+1) trajectory of n.

0, 2, 40, 6, 30, 46, 234, 14, 276, 40, 212, 58, 100, 248, 562, 30, 178, 294, 424, 60, 126, 234, 516, 82, 538, 126, 81178, 276, 366, 592, 80910, 62, 688, 212, 446, 330, 444, 462, 1894, 100, 81096, 168, 1090, 278, 416, 562, 80816, 130, 666, 588, 926, 178, 340

Offset: 1

Author

Jayanta Basu, Mar 05 2013

Keywords

• nonn

Examples

			a(5)=30 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.

Programs

Mathematica

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