A123780 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 4 which is flat, i.e., with all blocks in parallel position.
1, 4, 33, 294, 2951, 30668, 328999, 3596934, 39932206, 448517488, 5086259884, 58135266335
Offset: 1