A075481 - OEIS

A075481

Number of iteration that first becomes smaller than the initial value if Collatz-function (A006370) is iterated, starting with numbers of form 64n+47. Corresponds to selection of every 16th term from A074474.

89, 51, 14, 33, 22, 17, 14, 45, 27, 22, 14, 35, 17, 20, 14, 35, 22, 22, 14, 43, 22, 17, 14, 27, 128, 20, 14, 25, 17, 25, 14, 20, 22, 30, 14, 82, 20, 17, 14, 45, 22, 27, 14, 25, 17, 27, 14, 48, 20, 30, 14, 43, 30, 17, 14, 58, 61, 27, 14, 53, 17, 56, 14, 22, 30, 58, 14, 27, 53

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OFFSET

0,1

COMMENTS

Remark that initial values of form 64m+r, if r={3,11,19,27,35,43,51,55} provide first-sink-lengths {7,9,7,9,7,9,7,9} respectively; e.g. {64k+19,192k+58,96k+29,288k+88,144k+44,72k+22,36k+11} submerge first below initial value at the 7th term,36k+11<64k+19.

LINKS

Table of n, a(n) for n=0..68.

FORMULA

a(n)=A075473[64n+47], n=0, ..., 256

EXAMPLE

n=2: 64n+47=175,list={175,526,263,790,395,1186,593,1780, 890,445,1336,668,334,167,502,251....}, i.e. the 14th term=167 is the first that <175, the initial value, so a(2)=14.

CROSSREFS

Cf. A074473, A074474, A075476-A075483, A006370.

Sequence in context: A262093 A033409 A152160 * A104925 A096400 A074119

Adjacent sequences: A075478 A075479 A075480 * A075482 A075483 A075484

KEYWORD

nonn

AUTHOR

Labos Elemer, Sep 23 2002

STATUS

approved