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A224537 Least odd number d such that the Collatz iteration of d has the following property: if the length of the iteration is b and the maximum value occurs at c, the ratio c/b is the n-th Farey-like fraction. 1
1, 3, 5, 215, 21, 1625, 13, 901, 467, 771667051 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The Farey-like fractions are 1, 1/2, 1/3, 2/3, 1/4, 3/4, 1/5, 2/5, 3/5, 4/5, 1/6, 5/6,.... The numerators/denominators are in A038566/A038567. We conclude (unsurprisingly) that the maximum value of a Collatz iteration usually appears toward the beginning of the iteration.

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

Viewed as an irregular triangle, with 0's for unknown terms:

1

3,

5, 215,

21, 1625,

13, 901, 467, 771667051,

53, 0,

67, 35, 1815, 43641, 97, 0,

141, 23, 90435, 0,

93, 79, 15, 895, 763, 0,

61, 603, 1224211, 0,

37, 267, 59, 8857, 5793, 335737, 60221, 5434799, 0, 0

CROSSREFS

Cf. A224533.

Sequence in context: A092947 A104996 A211767 * A175133 A012817 A087367

Adjacent sequences:  A224534 A224535 A224536 * A224538 A224539 A224540

KEYWORD

nonn

AUTHOR

T. D. Noe, Apr 23 2013

STATUS

approved

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Last modified May 19 04:06 EDT 2019. Contains 323377 sequences. (Running on oeis4.)