A123829 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 2x4 which is symmetric after a rotation by 180 degrees.

1, 2, 44, 185, 3276, 15682, 282377, 1480410, 26264942

Offset

1,2

Links

Table of n, a(n) for n=1..9.

Index entry for sequences related to LEGO blocks

Crossrefs

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

Sequence in context: A007367 A006313 A059737 * A242856 A035605 A285746

Adjacent sequences: A123826 A123827 A123828 * A123830 A123831 A123832

Keyword

nonn

Author

Søren Eilers, Oct 29 2006

Status

approved