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%I #9 Aug 25 2013 05:13:47
%S 0,0,0,1,2,3,3,4,6,8,10,13,18,24,31,41,55,73,96,127,169,224,296,392,
%T 520,689,912,1208,1601,2121,2809,3721,4930,6531,8651,11460,15182,
%U 20112,26642,35293,46754,61936,82047,108689,143983,190737
%N The number of all possible covers of L-length line segment by 3-length line segments with allowed gaps < 3.
%C For n>2, a(n) = A017818(n+3).
%F G.f.: x^3*(1 + x + x^2)^2 / (1 - x^3 - x^4 - x^5).
%F a(0)=a(1)=a(2)=0; a(3)=1; a(4)=2; a(5)= a(6)=3; a(7)=4; a(n)= a(n-3) + a(n-4) + a(n-5).
%t CoefficientList[Series[(1 - x^3 - x^4 - x^5)^-1*(1 + x + x^2)^2*x^3 , {x,0, 100}],x]
%Y Third row of A228360.
%K nonn
%O 0,5
%A _Philipp O. Tsvetkov_, Aug 21 2013
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