A319326 a(n) is the number of column convex polyglasses (polyiamonds which need only touch at corners) with n cells.

2, 12, 84, 612, 4532, 33762, 252106, 1884120, 14084674, 105295512, 787178752

Offset

1,1

Comments

A polyglass is column convex if the intersection of its interior with any vertical line through the centers of the cells is connected.

Links

Table of n, a(n) for n=1..11.

Adam Gruber, Java program to count lattice animals.

Example

There are four triglasses that are not column convex. So a(2) = A319324(3) - 4 = 84.

Crossrefs

Cf. A319324 (fixed polyglasses), A319325 (row convex polyglasses), A319323 (column convex polyiamonds).

Sequence in context: A355378 A136278 A130464 * A214765 A006657 A105927

Adjacent sequences: A319323 A319324 A319325 * A319327 A319328 A319329

Keyword

nonn,more

Author

David Bevan, Sep 27 2018

Status

approved