4,1

Charles R Greathouse IV, Table of n, a(n) for n = 4..10000

a(4) = 3 as the fourth prime 7 divides 1001.

(PARI) a(n)=my(p=prime(n), m=Mod(1, p)); for(k=1, znorder(10*m), if(-1==m*=10, return(k))); 0 \\ Charles R Greathouse IV, Jun 18 2013

Sequence in context: A188938 A156368 A240665 * A238106 A087000 A289067

Adjacent sequences: A068955 A068956 A068957 * A068959 A068960 A068961

nonn

Amarnath Murthy, Apr 01 2002

More terms from Sascha Kurz, Jan 03 2003

approved