A130616 Number of triangular polyominoes (or polyiamonds) with perimeter at most n.

0, 0, 1, 2, 3, 7, 12, 28, 65, 185

Offset

1,4

Comments

Partial sums of A057729 - Number of triangular polyominoes (or polyiamonds) with perimeter n. a(n+2) >= A130867(n) - Triangular polyominoes (or polyiamonds) with n cells at most.

Links

Table of n, a(n) for n=1..10.

Crossrefs

Cf. A131481 (number of n-cell polyiamonds with perimeter n+2).

Sequence in context: A203837 A342132 A032173 * A089324 A339159 A297438

Adjacent sequences: A130613 A130614 A130615 * A130617 A130618 A130619

Keyword

hard,more,nonn

Author

Tanya Khovanova, Aug 10 2007

Extensions

Offset corrected by John Mason, Jan 16 2023

Status

approved