A319156 Number of ways to build a contiguous building with n LEGO blocks of size 1 X 2 which is flat, i.e., with all blocks in parallel position.

1, 3, 11, 44, 186, 814, 3656, 16731, 77705, 365095, 1731797, 8279363, 39845689, 192852359, 937986507, 4581678031, 22464030959, 110509938701, 545269104263, 2697646445713, 13378627003520, 66495716465315, 331167284581601, 1652340114446553, 8258197397705302

Offset

1,2

Links

Table of n, a(n) for n=1..25.

Rasmus Mølck Nilsson: On the number of flat LEGO structures, Master's thesis in Mathematics, University of Copenhagen, 2016.

Crossrefs

Cf. A123764, but here no identification up to rotation is performed.

Sequence in context: A121220 A068091 A001207 * A026887 A151106 A302186

Adjacent sequences: A319153 A319154 A319155 * A319157 A319158 A319159

Keyword

nonn

Author

Søren Eilers, Sep 12 2018

Status

approved