A123770 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 3.

1, 8, 152, 3594, 96105, 2734356, 81126946, 2480378897, 77597683206, 2472038270424

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: A367701 A221732 A249931 * A003400 A360338 A059510

Adjacent sequences: A123767 A123768 A123769 * A123771 A123772 A123773

Keyword

nonn,hard,more

Author

Søren Eilers, Oct 29 2006

Status

approved