For each cell of a polyomino let b be the number of cells that are in the same row or in the same column (including itself). Cells beyond gaps do not count. a(n) is the sum of the b values of all cells of all free polyominoes with n cells.

A365835

For each cell of a polyomino let b be the number of cells that are in the same row or in the same column (including itself). Cells beyond gaps do not count. a(n) is the sum of the b values of all cells of all free polyominoes with n cells.