OFFSET
1,2
LINKS
T. D. Noe, Table of n, a(n) for n=1..100
FORMULA
a(n) = floor(10^A002371(n)/prime(n)).
a(n) = 0 if and only if n = 1 or 3, corresponding to the primes 2 and 5, which are factors of 10. - Alonso del Arte, Apr 03 2020
ceiling(log_10(a(n))) = prime(n) - 1 if prime(n) is a full reptend prime (A001913). - Alonso del Arte, Apr 14 2020
EXAMPLE
1/7 = 0.142857142..., so a(4) = 142857.
1/11 = 0.09090909..., so a(5) = 9.
MATHEMATICA
primePer[1] = primePer[3] = 0; primePer[n_] := FromDigits[(d = RealDigits[1/Prime[n]])[[1, 1]]] * 10^d[[2]]; Array[ primePer, 15] (* Amiram Eldar, Apr 28 2020 *)
PROG
(PARI) f(n)=if(n<4, n==2, znorder(Mod(10, prime(n)))) \\ A002371
for(n=1, 100, print1(floor(10^f(n)/prime(n)), ", "))
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
N. J. A. Sloane, Mar 30 2001
EXTENSIONS
More terms from Klaus Brockhaus, Mar 30 2001
STATUS
approved