A123816 - OEIS

A123816

Number of ways to build a contiguous building with n LEGO blocks of size 1 X 8 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position.

15, 253, 5055, 106387, 2364993, 53883047, 1258407303, 29843705355

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

OFFSET

1,1

COMMENTS

The base block is not counted among the n and must be the only block in the bottom layer of the building.

LINKS

Table of n, a(n) for n=1..8.

CROSSREFS

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

Sequence in context: A116508 A055659 A218368 * A273921 A182607 A218284

Adjacent sequences: A123813 A123814 A123815 * A123817 A123818 A123819

KEYWORD

nonn,hard

AUTHOR

Søren Eilers, Oct 29 2006

STATUS

approved