A123835 Number of ways to build a contiguous building with n LEGO blocks of size 3 X 3 on top of a fixed block of the same size.

25, 757, 29925, 1281402, 59340183, 2862828262, 142920335981, 7311973715989

Offset: 1

Author

Søren Eilers, Oct 29 2006

Keywords

• nonn
• hard

Comments

The base block is not counted among the n and must be the only block in the bottom layer of the building

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