A178505 - OEIS

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A178505

Decimal form of the period of 1/n for n such that gcd(n,10)=1. Leading zeros are suppressed.

3, 142857, 1, 9, 76923, 588235294117647, 52631578947368421, 47619, 434782608695652173913, 37, 344827586206896551724137931, 32258064516129, 3, 27, 25641, 2439, 23255813953488372093

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OFFSET

1,1

COMMENTS

The numbers n are A045572, and the corresponding periods are A002329.

LINKS

Ray Chandler, Table of n, a(n) for n = 1..406 (terms up to 1000 digits)

FORMULA

a(n) = A060284(A045572(n+1)). [R. J. Mathar, Jun 26 2010]

EXAMPLE

3 is in the sequence because 1/3 = 0.3333...

142857 is in the sequence because 1/7 = 0.142857 142857 ...

1 is in the sequence because 1/9 = 0.1111....

MAPLE

with(numtheory): nn:= 100: T:=array(1..nn):k:=1: U:=array(1..nn):k:=1: for n from 2 to 200 do:x:=1/n:for p from 1 to 200 while(irem(10^p, n)<>1 or gcd(n, 10)<> 1) do:od: if irem(10^p, n) = 1 and gcd(n, 10) = 1 then y:=floor(x*10^p): T[k]:=y: U[k]:=n : k:=k+1:else fi:od:print(T):

CROSSREFS

Cf. A002329, A036275, A045572, A060284.

Sequence in context: A159577 A116536 A224241 * A306594 A003544 A250495

Adjacent sequences: A178502 A178503 A178504 * A178506 A178507 A178508

KEYWORD

nonn,base

AUTHOR

Michel Lagneau, May 29 2010

EXTENSIONS

Name corrected by T. D. Noe, Jul 07 2010

STATUS

approved