A123806 Number of ways to build a contiguous building with n LEGO blocks of size 1x7 on top of a fixed block of the same size.

62, 5188, 603490, 77670923, 10795814511, 1572624052679

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..6.

Crossrefs

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

Sequence in context: A042861 A056639 A289297 * A233340 A299826 A209905

Adjacent sequences: A123803 A123804 A123805 * A123807 A123808 A123809

Keyword

nonn,hard

Author

Søren Eilers, Oct 29 2006

Status

approved