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A123774 Number of ways to build a contiguous building with n LEGO blocks of size 1x3 on top of a fixed block of the same size. 0
14, 244, 5762, 147801, 4117161, 119893930, 3616711327, 111950012510, 3536272532516 (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..9.

CROSSREFS

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

Sequence in context: A286882 A326651 A055477 * A074815 A280122 A051622

Adjacent sequences:  A123771 A123772 A123773 * A123775 A123776 A123777

KEYWORD

nonn,hard

AUTHOR

Søren Eilers, Oct 29 2006

STATUS

approved

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Last modified September 22 07:34 EDT 2020. Contains 337289 sequences. (Running on oeis4.)