A007736 Period of repeating digits of 1/n in base 5.

1, 1, 2, 1, 1, 2, 6, 2, 6, 1, 5, 2, 4, 6, 2, 4, 16, 6, 9, 1, 6, 5, 22, 2, 1, 4, 18, 6, 14, 2, 3, 8, 10, 16, 6, 6, 36, 9, 4, 2, 20, 6, 42, 5, 6, 22, 46, 4, 42, 1, 16, 4, 52, 18, 5, 6, 18, 14, 29, 2, 30, 3, 6, 16, 4, 10, 22, 16, 22, 6, 5, 6, 72, 36, 2, 9, 30, 4, 39, 4, 54, 20, 82, 6, 16, 42, 14, 10, 44

Offset

1,3

Links

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

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

Mathematica

f[n_] := MultiplicativeOrder[5, n/(5^IntegerExponent[n, 5])]; Array[f, 80] (* Robert G. Wilson v, Jun 10 2011 *)
Table[Length[RealDigits[1/n, 5][[1, 1]]], {n, 90}]/.(0->1) (* Harvey P. Dale, Dec 28 2016 *)

Prog

(PARI) A007736(n, bas)={ local(p) ; for(sp=2, 1000000, for(s=1, sp-1, p=sp-s ; if( ((bas^p-1)*bas^s) % n == 0, return(p) ; ) ; ) ; ) ; return(-1) ; } { for(n=1, 100, print(n, " ", A007736(n, 5)) ; ) ; } - R. J. Mathar, Aug 30 2006
(PARI) a(n)=znorder(Mod(5, n/5^valuation(n, 5))) \\ Charles R Greathouse IV, Jun 10 2011

Crossrefs

Sequence in context: A123218 A298608 A327815 * A107042 A134830 A319031

Adjacent sequences: A007733 A007734 A007735 * A007737 A007738 A007739

Keyword

nonn,base

Author

N. J. A. Sloane, Hal Sampson (hals(AT)easynet.com), David W. Wilson

Status

approved