Sequence arising from enumeration of domino tilings of Aztec Pillow-like regions.

Terms

a(0) =0a(1) =2a(2) =6a(3) =26a(4) =90a(5) =302a(6) =966a(7) =3026a(8) =9330a(9) =28502a(10) =86526a(11) =261626a(12) =788970a(13) =2375102a(14) =7141686a(15) =21457826a(16) =64439010a(17) =193448102a(18) =580606446a(19) =1742343626a(20) =5228079450a(21) =15686335502a(22) =47063200806a(23) =141197991026a(24) =423610750290