A198592 Odd numbers producing 9 odd numbers in the Collatz iteration.

33, 65, 67, 131, 133, 261, 269, 273, 289, 525, 529, 533, 547, 555, 571, 577, 579, 583, 633, 635, 1045, 1059, 1077, 1093, 1099, 1111, 1143, 1155, 1157, 1167, 1177, 1267, 1271, 1273, 2101, 2117, 2123, 2133, 2161, 2189, 2199, 2221, 2285, 2309, 2317, 2321, 2333

Offset

1,1

Links

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

Mathematica

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; t = {}; Do[If[Length[Select[Collatz[n], OddQ]] == 9, AppendTo[t, n]], {n, 1, 10000, 2}]; t
col9Q[n_]:=Count[NestWhileList[If[EvenQ[#], #/2, 3#+1]&, n, #!=1&], _?(OddQ[#]&)]==9; Select[ Range[1, 2501, 2], col9Q] (* Harvey P. Dale, Dec 10 2023 *)

Crossrefs

Cf. A198584.

Sequence in context: A331071 A062059 A285317 * A325377 A061560 A118618

Adjacent sequences: A198589 A198590 A198591 * A198593 A198594 A198595

Keyword

nonn

Author

T. D. Noe, Oct 31 2011

Status

approved