Number of length n+3 0..1 arrays with at most two downsteps in every n consecutive neighbor pairs.

Terms

a(0) =16a(1) =32a(2) =64a(3) =128a(4) =245a(5) =442a(6) =753a(7) =1220a(8) =1894a(9) =2836a(10) =4118a(11) =5824a(12) =8051a(13) =10910a(14) =14527a(15) =19044a(16) =24620a(17) =31432a(18) =39676a(19) =49568a(20) =61345a(21) =75266a(22) =91613a(23) =110692a(24) =132834a(25) =158396a(26) =187762a(27) =221344a(28) =259583a(29) =302950