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

Author

T. D. Noe, Mar 26 2013

Keywords

• nonn

Examples

			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.
		

Links

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

Crossrefs

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

Programs

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