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A089947
G.f.: (1-x)^9/((1-5*x+6*x^2-4*x^3+x^4)*(-1+4*x-3*x^2+x^3)*(1-3*x+x^2)*(-1+2*x)).
1
1, 5, 25, 115, 500, 2092, 8512, 33910, 132892, 514079, 1968021, 7470434, 28160354, 105542777, 393672627, 1462503264, 5414896000, 19991387639, 73628208598, 270614786791, 992880076249, 3637400475618, 13308475404934, 48639360355243, 177597694845849
OFFSET
0,2
REFERENCES
A. Burstein and T. Mansour, Words restricted by 3-letter ..., Annals. Combin., 7 (2003), 1-14; see Th. 3.6, case k=5.
LINKS
A. Burstein and T. Mansour, Words restricted by 3-letter ....
Index entries for linear recurrences with constant coefficients, signature (14, -81, 254, -481, 588, -485, 270, -98, 21, -2).
MATHEMATICA
CoefficientList[Series[(1-x)^9/((1-5x+6x^2-4x^3+x^4)(-1+4x-3x^2+x^3)(1-3x+x^2)(-1+2x)), {x, 0, 30}], x] (* or *) LinearRecurrence[{14, -81, 254, -481, 588, -485, 270, -98, 21, -2}, {1, 5, 25, 115, 500, 2092, 8512, 33910, 132892, 514079}, 30] (* Harvey P. Dale, Oct 03 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 18 2004
STATUS
approved