Number of ways two L-tiles can be placed on an n X n square.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =20a(5) =87a(6) =244a(7) =545a(8) =1056a(9) =1855a(10) =3032a(11) =4689a(12) =6940a(13) =9911a(14) =13740a(15) =18577a(16) =24584a(17) =31935a(18) =40816a(19) =51425a(20) =63972a(21) =78679a(22) =95780a(23) =115521a(24) =138160a(25) =163967a(26) =193224a(27) =226225a(28) =263276a(29) =304695