A123834 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 3 X 3 which is symmetric after a rotation by 90 degrees.

1, 1, 1, 1, 7, 10, 13, 50, 190, 292, 403, 1873, 6982

Offset: 1

Author

Søren Eilers, Oct 29 2006

Keywords

• nonn

Links

• M. Abrahamsen and S. Eilers, On the asymptotic enumeration of LEGO structures, Exper Math. 20 (2) (2011) 145-152.
• B. Durhuus and S. Eilers, On the entropy of LEGO, arXiv:math.CO/0504039