A359526 Number of unbiased (balanced) free polyiamonds with 2n cells.

1, 2, 10, 44, 283, 1922, 14163, 107771, 841846

Offset

1,2

Comments

Define the bias of a polyiamond to be the difference between the number of black triangles and the number of white triangles when chessboard coloring is applied to the polyiamond. Unbiased polyiamonds are those having an equal number of black and white triangles. The sequence is defined for 2n rather than n as odd-sized polyiamonds are obviously biased.

Links

Table of n, a(n) for n=1..9.

Crossrefs

Cf. A000577, A234012.

Sequence in context: A105485 A151313 A144896 * A142983 A227852 A347524

Adjacent sequences: A359523 A359524 A359525 * A359527 A359528 A359529

Keyword

nonn,more

Author

John Mason, Jan 05 2023

Status

approved