A198591 Odd numbers producing 8 odd numbers in the Collatz iteration.

25, 49, 51, 99, 101, 197, 205, 217, 397, 405, 433, 435, 441, 475, 789, 821, 833, 857, 867, 869, 875, 883, 951, 953, 955, 1589, 1621, 1649, 1667, 1713, 1715, 1733, 1741, 1751, 1765, 1785, 1901, 1907, 1911, 3157, 3185, 3285, 3299, 3333, 3427, 3429, 3469, 3477

Offset: 1

Author

T. D. Noe, Oct 31 2011

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1938

Crossrefs

Cf. A198584.

Programs

Mathematica

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; t = {}; Do[If[Length[Select[Collatz[n], OddQ]] == 8, AppendTo[t, n]], {n, 1, 10000, 2}]; t