[seqfan] 2n-ominoes tiled by 1x2 rectangles

[David Scambler]

Has anyone counted free 2n-ominoes that can/cannot be tiled by 1x2 rectangles?

I don't think this is the same as https://oeis.org/A123764 because LEGO symmetry is only left-right.

A123764: "Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1x2 which is flat, i.e. with all blocks in parallel position."

dave