A213199 Numbers k whose Collatz (3x+1) trajectory includes at least one term that is greater than k.

3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 53, 54, 55, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81, 82, 83

Offset

1,1

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

Example

a(1) = 3 because 3 is the first number k whose trajectory goes above k.

Mathematica

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Select[Range[100], Max[Collatz[#]] > # &] (* T. D. Noe, Mar 01 2013 *)

Crossrefs

Cf. A033496, A222562, A222597.

Sequence in context: A136492 A062506 A308468 * A184987 A242437 A370301

Adjacent sequences: A213196 A213197 A213198 * A213200 A213201 A213202

Keyword

nonn

Author

Jayanta Basu, Mar 01 2013

Status

approved