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A123770 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 3. 0
1, 8, 152, 3594, 96105, 2734356, 81126946, 2480378897, 77597683206, 2472038270424 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..10.

S. Eilers, The LEGO counting problem, Amer. Math. Monthly, 123 (May 2016), 415-426.

Index entry for sequences related to LEGO blocks

CROSSREFS

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

Sequence in context: A053606 A221732 A249931 * A003400 A059510 A264708

Adjacent sequences:  A123767 A123768 A123769 * A123771 A123772 A123773

KEYWORD

nonn,hard,more

AUTHOR

Søren Eilers, Oct 29 2006

STATUS

approved

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Last modified July 6 10:05 EDT 2022. Contains 355108 sequences. (Running on oeis4.)