%I
%S 83,829,8286,82858,828571,8285715,82857143,828571429,8285714286,
%T 82857142858,828571428571,8285714285715,82857142857143,
%U 828571428571429,8285714285714286,82857142857142858,828571428571428571
%N a(n) is equal to the number of positive integers m less than or equal to 10^n such that m is not divisible by the prime 7 and is not divisible by at least one of the primes 2, 3 and 5.
%H Vincenzo Librandi, <a href="/A128950/b128950.txt">Table of n, a(n) for n = 2..1000</a>
%H Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Enumerative Formulas for Some Functions on Finite Sets</a>
%F a(n) = 10^n  floor(10^n/7)  floor(10^n/30) + floor(10^n/210).
%e a(6) = 10^6  floor(10^6/7)  floor(10^6/30) + floor(10^6/210) = 1000000  floor(142857.142...)  floor(33333.333...) + floor(4761.904...) = 1000000  142857  33333 + 4761 = 828571.
%p f := n>10^nfloor(10^n/7)floor(10^n/30)+floor(10^n/210);
%o (MAGMA) [10^nFloor(10^n/7)Floor(10^n/30)+Floor(10^n/210): n in [2..20]]; // _Vincenzo Librandi_, Oct 02 2011
%K nonn
%O 2,1
%A _Milan Janjic_, Apr 28 2007
%E Example edited by _Jon E. Schoenfield_, Nov 17 2018
