A123790 Number of ways to build a contiguous building with n LEGO blocks of size 1x5 on top of a fixed block of the same size.

34, 1516, 93664, 6366476, 468438942, 36108392112, 2882260782674

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..7.

Crossrefs

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

Sequence in context: A093550 A296587 A212735 * A297636 A212033 A202297

Adjacent sequences: A123787 A123788 A123789 * A123791 A123792 A123793

Keyword

nonn,hard

Author

Søren Eilers, Oct 29 2006

Status

approved