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A036275 The periodic part of the decimal expansion of 1/n. Any initial 0's are to be placed at end of cycle. 11
0, 0, 3, 0, 0, 6, 142857, 0, 1, 0, 90, 3, 769230, 714285, 6, 0, 5882352941176470, 5, 526315789473684210, 0, 476190, 45, 4347826086956521739130, 6, 0, 384615, 370, 571428, 3448275862068965517241379310, 3, 322580645161290, 0, 30, 2941176470588235, 285714, 7 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

LINKS

T. D. Noe, Table of n, a(n) for n=1..500

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

EXAMPLE

1/28 = .03571428571428571428571428571428571428571... and digit-cycle is 571428, so a(28)=571428.

MAPLE

isCycl := proc(n) local ifa, i ; if n <= 2 then RETURN(false) ; fi ; ifa := ifactors(n)[2] ; for i from 1 to nops(ifa) do if op(1, op(i, ifa)) <> 2 and op(1, op(i, ifa)) <> 5 then RETURN(true) ; fi ; od ; RETURN(false) ; end: A036275 := proc(n) local ifa, sh, lpow, mpow, r ; if not isCycl(n) then RETURN(0) ; else lpow:=1 ; while true do for mpow from lpow-1 to 0 by -1 do if (10^lpow-10^mpow) mod n =0 then r := (10^lpow-10^mpow)/n ; r := r mod (10^(lpow-mpow)-1) ; while r*10 < 10^(lpow-mpow) do r := 10*r ; od ; RETURN(r) ; fi ; od ; lpow := lpow+1 ; od ; fi ; end: for n from 1 to 60 do printf("%d %d ", n, A036275(n)) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 19 2006

MATHEMATICA

r[x_]:=RealDigits[1/x]; w[x_]:=First[r[x]]; f[x_]:=First[w[x]]; l[x_]:=Last[w[x]]; z[x_]:=Last[r[x]];

c[x_] := Which[IntegerQ[l[x]], 0, IntegerQ[f[x]]==False, FromDigits[f[x]], True, FromDigits[l[x]]]; Table[c[i], {i, 1, 36}] (from Hans Havermann, Oct 19 2006)

fc[n_] := Block[{q}, q = Last[First[RealDigits[1/n]]]; If[IntegerQ[q], q = {}]; FromDigits[q]]; Table[fc[n], {n, 40}] (*Chandler*)

CROSSREFS

Cf. A007732, A051626, A036275, A002371, A048595, A006883, A007498, A007615, A040017, A051627.

See also A060282, A060283, A060251.

Sequence in context: A135028 A110620 A060284 * A131436 A046765 A046777

Adjacent sequences:  A036272 A036273 A036274 * A036276 A036277 A036278

KEYWORD

base,nonn,easy,nice

AUTHOR

Floor van Lamoen (fvlamoen(AT)hotmail.com)

EXTENSIONS

Corrected and extended by N. J. A. Sloane (njas(AT)research.att.com).

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Last modified February 17 13:28 EST 2012. Contains 206031 sequences.