A243628 Odd numbers producing 30 even numbers in the Collatz iteration.

185, 187, 191, 541, 545, 551, 557, 561, 563, 575, 607, 1629, 1635, 1637, 1655, 1659, 1671, 1677, 1681, 1683, 1685, 1687, 1725, 1755, 1803, 1821, 1825, 1833, 2007, 2011, 4885, 4917, 4929, 4953, 4963, 4965, 4979, 5015, 5017, 5029, 5041, 5043, 5045, 5061, 5077, 5081, 5091, 5121

Offset

1,1

Comments

See row 30 of A199636.

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..697

Mathematica

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; t = {}; Do[If[Length[Select[Collatz[n], EvenQ]] == 30, AppendTo[t, n]], {n, 1, 100000, 2}]; t
on30Q[n_]:=Count[NestWhileList[If[EvenQ[#], #/2, 3#+1]&, n, #!=1&], _?EvenQ] ==30; Select[Range[1, 5131, 2], on30Q] (* Harvey P. Dale, Mar 18 2023 *)

Crossrefs

Cf. A199636, A199817, A199818.

Sequence in context: A194614 A232915 A139265 * A353388 A262053 A362096

Adjacent sequences: A243625 A243626 A243627 * A243629 A243630 A243631

Keyword

nonn,fini,less

Author

Vincenzo Librandi, Jun 08 2014

Status

approved