A176920 - OEIS

A176920

Period of decimal representation of 1/n^2.

1, 1, 1, 1, 1, 1, 42, 1, 9, 1, 22, 1, 78, 42, 1, 1, 272, 9, 342, 1, 42, 22, 506, 1, 1, 78, 81, 42, 812, 1, 465, 1, 22, 272, 42, 9, 111, 342, 78, 1, 205, 42, 903, 22, 9, 506, 2162, 1, 2058, 1, 272, 78, 689, 81, 22, 42, 342, 812, 3422, 1, 3660, 465, 126, 1, 78, 22, 2211, 272, 506

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OFFSET

1,7

COMMENTS

term #7=42; 1/7^2= 0. 020408163265306122448979591836734693877551` 020408163265306122448979591836734693877551` 020408163265306122448979591836734693877551` 02040816326530612244897959183673469..

LINKS

Table of n, a(n) for n=1..69.

MATHEMATICA

DigitCycleLength[r_Rational, b_Integer?Positive]:=MultiplicativeOrder[b, FixedPoint[Quotient[ #, GCD[ #, b]]&, Denominator[r]]]; Table[If[n<2, 1, DigitCycleLength[1/n^2, 10]], {n, 5!}]

CROSSREFS

Cf. A007732

Sequence in context: A263288 A216799 A203484 * A037938 A371699 A091747

Adjacent sequences: A176917 A176918 A176919 * A176921 A176922 A176923

KEYWORD

nonn,base

AUTHOR

Vladimir Joseph Stephan Orlovsky, Apr 29 2010

STATUS

approved