OFFSET
2,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 2..1000
Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets
FORMULA
a(n) = 10^n - floor(10^n/2) - floor(10^n/105) + floor(10^n/210).
EXAMPLE
a(6) = 10^6 - floor(10^6/2) - floor(10^6/105) + floor(10^6/210) = 1000000 - floor(500000) - floor(9523.809...) + floor(4761.904...) = 1000000 - 500000 - 9523 + 4761 = 495238. - Jon E. Schoenfield, Nov 18 2018
MAPLE
f := n->10^n-floor(10^n/2)-floor(10^n/105)+floor(10^n/210);
PROG
(Magma) [10^n-Floor(10^n/2)-Floor(10^n/105)+Floor(10^n/210): n in [2..20]]; // Vincenzo Librandi, Oct 02 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Milan Janjic, Apr 28 2007
STATUS
approved