

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


COMMENTS

For n>1, a(n) = A134816(n).


LINKS

Table of n, a(n) for n=0..48.
Index entries for linear recurrences with constant coefficients, signature (0,1,1)


FORMULA

G.f.: x^2*(1+x)^2/(1x^2x^3).
a(n) = a(n2) +a(n3) for n>2.
a(n) = A000931(n+5), n>1.  R. J. Mathar, Sep 02 2013


MATHEMATICA

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


CROSSREFS

Second row of A228360.
The following are basically all variants of the same sequence: A000931, A078027, A096231, A124745, A133034, A134816, A164001, A182097, A228361 and probably A020720. However, each one has its own special features and deserves its own entry.
Sequence in context: A000931 A078027 A134816 * A182097 A290697 A290821
Adjacent sequences: A228358 A228359 A228360 * A228362 A228363 A228364


KEYWORD

nonn,easy


AUTHOR

Philipp O. Tsvetkov, Aug 21 2013


STATUS

approved



