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A051628 Number of digits in decimal expansion of 1/n before the periodic part begins. 3
0, 1, 0, 2, 1, 1, 0, 3, 0, 1, 0, 2, 0, 1, 1, 4, 0, 1, 0, 2, 0, 1, 0, 3, 2, 1, 0, 2, 0, 1, 0, 5, 0, 1, 1, 2, 0, 1, 0, 3, 0, 1, 0, 2, 1, 1, 0, 4, 0, 2, 0, 2, 0, 1, 1, 3, 0, 1, 0, 2, 0, 1, 0, 6, 1, 1, 0, 2, 0, 1, 0, 3, 0, 1, 2, 2, 0, 1, 0, 4, 0, 1, 0, 2, 1, 1, 0, 3, 0, 1, 0, 2, 0, 1, 1, 5, 0, 1, 0, 2, 0, 1, 0, 3, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

L. Lopes, POLYA problem

Index entries for sequences related to decimal expansion of 1/n

FORMULA

for n>1, a(n)=max(i, j) where n=2^i*3^x*5^j*... is the prime decomposition of n.

EXAMPLE

1/8 = .1250000... so a(8)=3, 1/15 = .0666666..., so a(15)=1.

MATHEMATICA

(* f parses output from RealDigits *) f[{{r__Integer, {__}}, k_ /; k <= 0}] := Length[{r}]-k; f[{{r__Integer}, k_ /; k <= 0}] := Length[{r}]-k; f[{{{r__Integer}}, k_ /; k <= 0}] := -k; f[{{{r__Integer, z : (0) ..}}, k_ /; k <= 0}] := -k-Length[{z}]; a[n_] := f[RealDigits[1/n]]; a[1]=0; Table[a[n], {n, 1, 105}]; (* Jean-François Alcover, Jun 29 2012 *)

CROSSREFS

Sequence in context: A110962 A065715 A180984 * A163540 A127967 A147602

Adjacent sequences:  A051625 A051626 A051627 * A051629 A051630 A051631

KEYWORD

nonn,nice,easy,base

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Michael Lugo (mlugo(AT)thelabelguy.com), Dec 22 1999

More terms from Franklin T. Adams-Watters, May 05 2006

STATUS

approved

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Last modified January 20 04:21 EST 2019. Contains 319323 sequences. (Running on oeis4.)