a(n) is the number of dominoes, among all domino tilings of the 2 X n rectangle, sharing a length-2 side with the boundary of the rectangle.

A320947

a(n) is the number of dominoes, among all domino tilings of the 2 X n rectangle, sharing a length-2 side with the boundary of the rectangle.

Terms

    a(0) =1a(1) =4a(2) =8a(3) =16a(4) =30a(5) =56a(6) =102a(7) =184a(8) =328a(9) =580a(10) =1018a(11) =1776a(12) =3082a(13) =5324a(14) =9160a(15) =15704a(16) =26838a(17) =45736a(18) =77742a(19) =131840a(20) =223112a(21) =376844a(22) =635378a(23) =1069536a(24) =1797650a(25) =3017236a(26) =5057672a(27) =8467744a(28) =14161038a(29) =23657240

External references