A223700 The maximum value of the Collatz (3x+1) iteration beginning at A223699(n).

1, 2, 4, 8, 16, 32, 64, 20, 40, 80, 160, 52, 96, 208, 68, 136, 280, 88, 184, 56, 112, 232, 72, 148, 304, 100, 196, 400, 808, 260, 520, 1048, 13120, 4372, 9232, 472, 916, 1888, 628, 1264, 2536, 4912, 1672, 3256, 39364, 2248, 740, 1480, 2968, 5992, 1972, 3844

Offset

1,2

Links

T. D. Noe, Table of n, a(n) for n = 1..800

Example

The Collatz iteration of 15 is {15, 46, 23, 70, 35, 106, 53, 160, 80, 40, 20, 10, 5, 16, 8, 4, 2, 1}. The maximum is 160, which occurs at position 11, counting from the right. Hence, a(11) = 160 because no number smaller than 15 has its maximum value at the 11 position.

Mathematica

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; t= Table[c = Reverse[Collatz[n]]; Position[c, Max[c]][[1, 1]], {n, 10000}]; t3 = {}; n = 0; While[n++; p = Position[t, n, 1, 1]; p != {}, c = Collatz[p[[1, 1]]]; AppendTo[t3, Max[c]]]; t3

Crossrefs

Cf. A070165 (Collatz iteration of n), A223699.

Sequence in context: A160686 A201920 A343926 * A036140 A036138 A000855

Adjacent sequences: A223697 A223698 A223699 * A223701 A223702 A223703

Keyword

nonn

Author

T. D. Noe, Mar 26 2013

Status

approved