A067703 Terms in the decimal expansion of 1/(7*5^n) before the block of decimals 142857 (the period of 1/7) appears.

2857, 57, 1, 22857, 457, 9, 182857, 3657, 73, 1462857, 29257, 585, 11702857, 234057, 4681, 93622857, 1872457, 37449, 748982857, 14979657, 299593, 5991862857, 119837257, 2396745, 47934902857, 958698057, 19173961

Offset: 1

Author

Benoit Cloitre, Feb 05 2002; revised Dec 11, 2004

Keywords

• nonn
• base

Comments

Example: 1/(7*5^4)=0.00022857(142857) hence a(4)=22857

Crossrefs

Cf. A067556.

Programs

PARI

a(n)=if(n<0, 0, s=1; while(frac(10^s/7/5^n-1/7)>0, s++); floor(10^s/7/5^n)) \\ Colin Barker, Jun 16 2013

Formula

Empirical g.f.: x*(-56*x^2-2800*x+2857) / (8*x^4-8*x^3-x+1). - Colin Barker, Jun 16 2013

Extensions

a(12) corrected by Colin Barker, Jun 16 2013