A113174 Number of fixed 3D piled polyominoes: polycubes with fixed orientation, with no cubes "sitting on air".

1, 3, 11, 44, 184, 792, 3484, 15592, 70745, 324561, 1502511, 7007929, 32892778, 155221536, 735915652, 3503270920, 16737092549, 80218277681, 385574074383, 1858059853316, 8974761939239, 43441619693731, 210682920968681

Offset: 1

Author

Franklin T. Adams-Watters, Oct 15 2005

Keywords

• nonn

Examples

			For n = 4, there are 4 orientations of the angled tricube excluded: those which set it on a point; this leaves 8 orientations of the angled tricube and 3 of the straight tricube.
		

Crossrefs

Cf. A001168, A001931 (fixed polycubes).

Formula

a(n) = sum_{m=1}^n A001168(m)*C(n-1, m-1). If both sequences are shifted left, binomial transform of A001168.

Extensions

Corrected by Franklin T. Adams-Watters, Oct 25 2006