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A199636 Irregular rows of odd numbers that produce n even numbers in their Collatz iteration. 6
5, 3, 21, 13, 85, 17, 53, 11, 35, 113, 341, 7, 23, 69, 75, 213, 227, 15, 45, 141, 151, 453, 1365, 9, 29, 93, 277, 301, 853, 909, 19, 61, 181, 201, 565, 605, 1813, 5461, 37, 117, 369, 373, 401, 403, 1109, 1137, 1205, 3413, 3637, 25, 77, 81, 241, 245, 267, 725 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,1

COMMENTS

It is conjectured that every odd number greater than 1 eventually appears in this sequence. The smallest and largest terms in row n are A199637(n) and A199638(n). The number of terms in row n is A131450(n) for n > 3.

The 10th and 20th rows are A199817 and A199818.

LINKS

T. D. Noe, Rows n = 4..33, flattened

MATHEMATICA

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; nn = 16; t = Table[{}, {nn}]; Do[len = Length[Select[Collatz[n], EvenQ]]; If[0 < len <= nn, AppendTo[t[[len]], n]], {n, 1, 25000, 2}]; t

CROSSREFS

Sequence in context: A099730 A072800 A199637 * A324038 A221473 A199638

Adjacent sequences:  A199633 A199634 A199635 * A199637 A199638 A199639

KEYWORD

nonn,tabf

AUTHOR

T. D. Noe, Nov 14 2011

STATUS

approved

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Last modified June 17 19:57 EDT 2021. Contains 345085 sequences. (Running on oeis4.)