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A198587
Odd numbers producing 4 odd numbers in the Collatz iteration.
3
17, 35, 69, 75, 141, 151, 277, 301, 565, 605, 1109, 1137, 1205, 2261, 2275, 2417, 2421, 4437, 4549, 4821, 4835, 4849, 9045, 9101, 9669, 9685, 9699, 17749, 18197, 19285, 19341, 19397, 19417, 36181, 36405, 38677, 38741, 38797, 38833, 38835, 70997, 72789, 72817
OFFSET
1,1
LINKS
Vincenzo Librandi and T. D. Noe, Table of n, a(n) for n = 1..287 (first 134 terms from Vincenzo Librandi)
MATHEMATICA
Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; t = {}; Do[If[Length[Select[Collatz[n], OddQ]] == 4, AppendTo[t, n]], {n, 1, 100000, 2}]; t
CROSSREFS
Cf. A198584.
Sequence in context: A239129 A212427 A195047 * A041570 A041572 A146729
KEYWORD
nonn
AUTHOR
T. D. Noe, Oct 31 2011
STATUS
approved