A187336 - OEIS

%I #7 Mar 20 2013 06:12:14

%S 0,0,3,6,8,10,15,15,18,21,23,25,30,30,33,36,38,40,45,45,48,51,53,55,

%T 60,60,63,66,68,70,75,75,78,81,83,85,90,90,93,96,98,100,105,105,108,

%U 111,113,115,120,120,123,126,128,130,135,135,138,141,143,145,150,150,153,156,158,160,165,165,168,171,173,175,180,180,183,186,188,190,195,195,198,201,203,205,210,210,213,216,218,220,225,225,228,231,233,235,240,240,243,246,248,250,255,255,258,261,263,265,270,270

%N Sum{floor(kn/6), k=1,2,3,4,5}.

%F a(n)=Sum{floor(kn/6), k=1,2,3,4,5}.

%F Empirical g.f.: x^2*(5*x^4+2*x^3+2*x^2+3*x+3) / ((x-1)^2*(x+1)*(x^2-x+1)*(x^2+x+1)). - _Colin Barker_, Mar 20 2013

%t Table[Sum[Floor[k*n/6], {k,1,5}],{n,0,200}]

%K nonn

%O 0,3

%A _Clark Kimberling_, Mar 08 2011