A229737 - OEIS

A229737

G.f.: x^2*(1-x)*(1-4*x+4*x^2+x^3)/((1-2*x)^2*(1-3*x+x^2)).

0, 0, 1, 2, 5, 14, 40, 114, 322, 900, 2490, 6826, 18564, 50146, 134690, 360068, 958826, 2545082, 6737860, 17799570, 46939378, 123608388, 325130970, 854405962, 2243591940, 5887904194, 15444237890, 40495141124, 106146043082, 278161091930, 728790217540, 1909149084786, 5000603193874, 13096687028676, 34297779391290

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OFFSET

0,4

LINKS

Table of n, a(n) for n=0..34.

D. Battaglino, J. M. Fedou, S. Rinaldi and S. Socci, The number of k-parallelogram polyominoes, FPSAC 2013 Paris, France DMTCS Proc. AS, 2013, 1143-1154. hal-01229685.

Index entries for linear recurrences with constant coefficients, signature (7,-17,16,-4).

MATHEMATICA

CoefficientList[Series[x^2*(1 - x)*(1 - 4*x + 4*x^2 + x^3)/((1 - 2*x)^2*(1 - 3*x + x^2)), {x, 0, 34}], x] (* Amiram Eldar, Oct 08 2020 *)

CROSSREFS

Sequence in context: A111109 A081908 A221677 * A059505 A159035 A117189

Adjacent sequences: A229734 A229735 A229736 * A229738 A229739 A229740

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Oct 04 2013

STATUS

approved