Tilings related by a symmetry of the polyomino that is not a symmetry of the tiling count as distinct (thus, the square tetromino counts as being tiled in two distinct ways).
Table of n, a(n) for n=1..9.
Cf. A056785, A056786, A213376, A213378.
Sequence in context: A276315 A145329 A051643 * A216583 A154644 A000891
Adjacent sequences: A213374 A213375 A213376 * A213378 A213379 A213380
Joseph Myers, Jun 10 2012