

A228361


The number of all possible covers of Llength line segment by 2length line segments with allowed gaps < 2.


13



0, 0, 1, 2, 2, 3, 4, 5, 7, 9, 12, 16, 21, 28, 37, 49, 65, 86, 114, 151, 200, 265, 351, 465, 616, 816, 1081, 1432, 1897, 2513, 3329, 4410, 5842, 7739, 10252, 13581, 17991, 23833, 31572, 41824, 55405, 73396, 97229, 128801, 170625, 226030, 299426, 396655, 525456
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OFFSET

0,4


LINKS



FORMULA

G.f.: x^2*(1+x)^2/(1x^2x^3).
a(n) = a(n2) +a(n3) for n >= 5.


MATHEMATICA

CoefficientList[Series[(1  x^2  x^3)^1 (1 + x)^2 x^2 , {x, 0, 100}], x]


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



STATUS

approved



