A122060 Position in decimal expansion of 1/n where repetition begins.

2, 3, 2, 4, 3, 3, 7, 5, 2, 3, 3, 4, 7, 8, 3, 6, 17, 3, 19, 4, 7, 4, 23, 5, 4, 8, 4, 11, 29, 3

Offset: 1

Author

Ben Paul Thurston, Sep 14 2006

Keywords

• nonn
• base

Comments

If 1/n = 0.XYYYYY... then sequence gives index of first digit of the second Y.

a(4) = 4 and a(p) = p for primes p = {7, 17, 19, 23, 29, 47, 59, 61, 97, ...} = A001913(n) Cyclic numbers: primes with primitive root 10. - Alexander Adamchuk, Jan 28 2007

Examples

			a(4) = 4 because in 0.2500 the zero begins repeating at the fourth position.
a(17) = 17 because 0.05882352941176470588... begins repeating at the 17th position.
		

Crossrefs

Cf. A001913, A002371.

Formula

a(n)=A121341(n)+2 if 1/n terminates, else a(n)=A121341(n)+1. - R. J. Mathar, Sep 20 2006