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A275907
Expansion of (1+x-x^3) / (1-4*x-x^4-x^5).
1
1, 5, 20, 79, 317, 1274, 5121, 20583, 82728, 332503, 1336407, 5371332, 21588639, 86769787, 348748058, 1401699971, 5633759855, 22643397846, 91009109229, 365786884945, 1470182999606, 5909009156125, 23749689131575, 95455552520474, 383658179966447, 1542011912021519, 6197706346373776
OFFSET
0,2
LINKS
T. Doslic, T. Short, Maximal matchings in polyspiro and benzenoid chains, arXiv:1511.00590, [math.CO], 2015. See Th. 4.4.
FORMULA
G.f.: (1+x-x^3) / (1-4*x-x^4-x^5).
a(n) = 4*a(n-1)+a(n-4)+a(n-5) for n>4. - Colin Barker, Aug 26 2016
MATHEMATICA
CoefficientList[Series[(1 + x - x^3)/(1 - 4*x - x^4 - x^5), {x, 0, 30}], x] (* Wesley Ivan Hurt, Sep 05 2022 *)
PROG
(PARI) Vec((1+x-x^3)/(1-4*x-x^4-x^5) + O(x^30)) \\ Colin Barker, Aug 26 2016
CROSSREFS
Sequence in context: A028814 A346394 A079820 * A117422 A154639 A214939
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Aug 25 2016
STATUS
approved