A112390 Triangle read by rows: T(n,k) is the number of ways of building a building of height k using n 2 X 4 LEGO blocks, counted up to symmetry (for 2 <= k <= n).

24, 500, 1060, 11707, 59201, 48672, 248688, 3203175, 4425804, 2238736, 7946227, 162216127, 359949655, 282010252, 102981504

Offset

2,1

References

Anthony Lane, The Joy of Bricks, The New Yorker, Apr 27-May 04, 1998, pp. 96-103.

Links

Table of n, a(n) for n=2..16.

B. Durhuus and S. Eilers, On entropy of LEGO, arXiv:math/0504039 [math.CO], 2005.

S. Eilers, A LEGO Counting problem.

Index entry for sequences related to LEGO blocks.

Example

Triangle begins:
       24;
      500,      1060;
    11707,     59201,     48672;
   248688,   3203175,   4425804,   2238736;
  7946227, 162216127, 359949655, 282010252, 102981504;

Crossrefs

Cf. A112389.

Sequence in context: A260964 A186863 A004383 * A166757 A289833 A242524

Adjacent sequences: A112387 A112388 A112389 * A112391 A112392 A112393

Keyword

nonn,tabl,more

Author

N. J. A. Sloane, Dec 06 2005

Extensions

Thanks to Gerald McGarvey, Christian Schroeder and Jud McCranie, who contributed to this entry.

Status

approved