Number of simple perfect squared rectangles of order n up to symmetry.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =2a(9) =6a(10) =22a(11) =67a(12) =213a(13) =744a(14) =2609a(15) =9016a(16) =31426a(17) =110381a(18) =390223a(19) =1383905a(20) =4931308a(21) =17633773a(22) =63301427a(23) =228130926a(24) =825229110a(25) =2994833854