OFFSET
0,4
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..10000
FORMULA
a(n) = floor(n/2) + floor(n/3) + floor(n/4) + floor(n/5).
a(n) = -a(n-1) - a(n-2) + a(n-4) + 2*a(n-5) + 2*a(n-6) + a(n-7) - a(n-9) - a(n-10) - a(n-11).
G.f.: x^2*(2*x^4 + 3*x^3 + 3*x^2 + 2*x + 1)*(2*x^4 + x^3 + 2*x^2 + x + 1) / ( (1+x)*(1 + x + x^2)*(x^4 + x^3 + x^2 + x + 1)*(x^2+1)*(x-1)^2 ). - R. J. Mathar, Mar 08 2011
MATHEMATICA
Table[Floor[n/2]+Floor[n/3]+Floor[n/4]+Floor[n/5], {n, 0, 120}]
Table[Total[Floor[n/Range[2, 5]]], {n, 0, 120}] (* Harvey P. Dale, Nov 22 2015 *)
PROG
(Magma) [Floor(n/2)+Floor(n/3)+Floor(n/4)+Floor(n/5): n in [0..130] ]; // Vincenzo Librandi, Jul 18 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Mar 08 2011
STATUS
approved