A123812 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 8 which is flat, i.e., with all blocks in parallel position.

1, 8, 145, 2884, 62517, 1404472, 32430749, 763219988, 18231473349

Offset

1,2

Links

Table of n, a(n) for n=1..9.

Crossrefs

Cf. A112389, A123762 - A123827, A123829 - A123849.

Sequence in context: A071305 A172150 A105046 * A064331 A230938 A351922

Adjacent sequences: A123809 A123810 A123811 * A123813 A123814 A123815

Keyword

nonn,hard

Author

Søren Eilers, Oct 29 2006

Status

approved