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

1,2

Links

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

Example

a(5)=30 since Collatz trajectory of 5 is 5,16,8,4,2,1.

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 *)

Crossrefs

Cf. A033493.

Sequence in context: A232086 A356683 A047660 * A349717 A349726 A275547

Adjacent sequences: A213906 A213907 A213908 * A213910 A213911 A213912

Keyword

nonn

Author

Jayanta Basu, Mar 05 2013

Status

approved