Number of domino tilings of a 9-pillow of order n.

Terms

a(0) =1a(1) =2a(2) =5a(3) =13a(4) =34a(5) =89a(6) =356a(7) =1737a(8) =9065a(9) =49610a(10) =325832a(11) =2795584a(12) =28098632a(13) =310726442a(14) =3877921669a(15) =58896208285