A123778 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1x4.

1, 12, 425, 17610, 818803, 40408828, 2078794759, 110210311068

Offset

1,2

Links

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

Crossrefs

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

Sequence in context: A000897 A036687 A262858 * A347795 A129006 A067429

Adjacent sequences: A123775 A123776 A123777 * A123779 A123780 A123781

Keyword

nonn,hard

Author

Søren Eilers, Oct 29 2006

Status

approved