Small-number statistic from the enumeration of domino tilings of a 3-pillow of order n.

Terms

a(0) =1a(1) =2a(2) =5a(3) =5a(4) =13a(5) =16a(6) =37a(7) =45a(8) =109a(9) =130a(10) =313a(11) =377a(12) =905a(13) =1088a(14) =2617a(15) =3145a(16) =7561a(17) =9090a(18) =21853a(19) =26269a(20) =63157a(21) =75920a(22) =182525a(23) =219413a(24) =527509a(25) =634114a(26) =1524529a(27) =1832625a(28) =4405969a(29) =5296384