A390209 - OEIS

A390209

The number of domino stacks with n dominos.

1, 2, 5, 11, 23, 45, 85, 154, 272, 468, 788, 1301, 2113, 3377, 5324, 8287, 12749, 19403, 29240, 43655, 64620, 94884, 138271, 200067, 287548, 410660, 582970, 822870, 1155205, 1613398, 2242248, 3101545, 4270861, 5855676, 7995385, 10873613, 14731521, 19884853, 26745909, 35851506, 47898765, 63790636, 84693769, 112111789, 147978206, 194773508, 255672902, 334732115

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..1000

Tricia Muldoon Brown, Convex Domino Towers, J. Int. Seq., Vol. 20 (2017), Article 17.3.1.

MAPLE

A275204 := proc(n, k)

option remember;

if k < 1 or k > n then

0 ;

elif n =k then

else

add( (2*(k-i)+1)*procname(n-k, i), i=1..k) ;

end if;

end proc:

seq(add(A275204(n, k), k=1..n), n=1..90) ;

MATHEMATICA

T[n_, k_] := T[n, k] = If[n < 1, 0, If[k == n, 1, Sum[(2*(k-i) + 1) * T[n-k, i], {i, 1, k}]]]; a[n_] := Sum[T[n, k], {k, 1, n}]; Array[a, 48] (* Amiram Eldar, Oct 31 2025 *)

CROSSREFS

Row sums of A275204.

Sequence in context: A064934 A227637 A171985 * A354044 A005986 A333396

Adjacent sequences: A390206 A390207 A390208 * A390210 A390211 A390212

KEYWORD

nonn

AUTHOR

R. J. Mathar, Oct 29 2025

STATUS

approved