A352907 Records in the number of iterations in the 3x+1 sequences required to reach a power of 2.

0, 3, 4, 12, 15, 16, 19, 107, 108, 111, 114, 117, 120, 123, 126, 139, 140, 166, 174, 177, 178, 204, 212, 233, 257, 263, 271, 274, 277, 303, 306, 319, 335, 346, 349, 370, 378, 381, 438, 444, 465, 504, 520, 523, 526, 552, 555, 558, 579, 592, 608, 660, 681, 684

Offset

1,2

Comments

Records of the number of nonpowers of 2 in the sequences 3x+1.

Is this a finite sequence?

Links

Paolo Xausa, Table of n, a(n) for n = 1..147 (b-file generated using Eric Roosendaal's data and Omar E. Pol's comment in A006877).

Eric Roosendaal, 3x+1 Delay Records

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

Mathematica

f[n_] := -1 + Length @ NestWhileList[If[OddQ[#], 3*# + 1, #/2] &, n, !IntegerQ @ Log[2, #] &]; Union @ FoldList[Max, Array[f, 10^5]] (* Amiram Eldar, Apr 08 2022 *)

Crossrefs

Records in A208981.

Cf. A352939 (first differences).

Cf. A347270 (gives all 3x+1 sequences).

Cf. A006370, A006877, A014682, A056959, A057716, A347272, A347519, A347532, A353265.

Sequence in context: A336612 A070287 A124637 * A047173 A116653 A218967

Adjacent sequences: A352904 A352905 A352906 * A352908 A352909 A352910

Keyword

nonn

Author

Omar E. Pol, Apr 07 2022

Extensions

More terms from Alois P. Heinz, Apr 07 2022

Status

approved