A055582 Sixth column of triangle A055252.

1, 9, 48, 198, 699, 2223, 6562, 18324, 49029, 126837, 319332, 786258, 1900351, 4521771, 10616598, 24641280, 56622825, 128974545, 291503800, 654311070, 1459617411, 3238002279, 7147093578, 15703473708, 34359737869, 74893491693

Offset

0,2

Links

Michael De Vlieger, Table of n, a(n) for n = 0..3296

Robert Davis, Greg Simay, Further Combinatorics and Applications of Two-Toned Tilings, arXiv:2001.11089 [math.CO], 2020.

Index entries for linear recurrences with constant coefficients, signature (9, -33, 63, -66, 36, -8).

Formula

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

a(n)= A055252(n+5, 5). a(n)= sum(a(j), j=0..n-1)+A034009(n), n >= 1.

a(n)= (n^2 - 3*n + 8)*(2^(n+3) -1)/2 - 9*(n+3). [Yahia Kahloune, Aug 11 2013]

Mathematica

CoefficientList[Series[1/(((1 - 2 x)^3) (1 - x)^3), {x, 0, 25}], x] (* Michael De Vlieger, Apr 23 2020 *)

Crossrefs

Cf. A055252, A055249, A034009, partial sums of A055581.

Sequence in context: A212107 A073979 A018984 * A359175 A054460 A115053

Adjacent sequences: A055579 A055580 A055581 * A055583 A055584 A055585

Keyword

easy,nonn

Author

Wolfdieter Lang, May 26 2000

Status

approved