A087226 LCM of terms in Collatz (3x+1) function initiated at n.

1, 2, 240, 4, 80, 240, 1361360, 8, 12252240, 80, 194480, 240, 1040, 1361360, 4095840, 16, 17680, 12252240, 107158480, 80, 1344, 194480, 1365280, 240, 535792400, 1040, 44841486948146266934850832405421294927083491752830032389039800908293040266400

Offset

1,2

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for sequences related to 3x+1 (or Collatz) problem

Index entries for sequences related to lcm's

Example

n=9: list={9,28,14,7,22,11,34,17,52,26,13,40,20,10,5,16,8,4,2,1};
LCM = 2*2*2*2*3*3*5*7*11*13*17 = 12252240.

Mathematica

c[x_] := (1-Mod[x, 2])*(x/2)+Mod[x, 2]*(3*x+1); c[1]=1; fpl[x_] := Delete[FixedPointList[c, x], -1] Table[Apply[LCM, fpl[w]], {w, 1, 32}]
Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Table[LCM @@ Collatz[n], {n, 27}] (* T. D. Noe, May 15 2013 *)

Prog

(Haskell)
a087226 = foldl1 lcm . a070165_row  -- Reinhard Zumkeller, May 16 2013

Crossrefs

Cf. A006370.

Cf. A070165, A225784.

Sequence in context: A013473 A212839 A225784 * A217972 A071967 A024348

Adjacent sequences: A087223 A087224 A087225 * A087227 A087228 A087229

Keyword

nonn

Author

Labos Elemer, Aug 28 2003

Status

approved