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

Offset: 1

Author

Michel Lagneau, May 29 2010

Keywords

• nonn
• base

Comments

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

Examples

			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....
		

Links

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

Crossrefs

Cf. A002329, A036275, A045572, A060284.

Programs

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):

Formula

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

Extensions

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