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, 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

Author

N. J. A. Sloane, Jan 18 2004

Keywords

• nonn

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).

Crossrefs

Cf. A061667, A089883, A089932.

Programs

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 *)