Number of length-5 0..n arrays with no adjacent pair x,x+1 repeated.

Terms

a(0) =1a(1) =26a(2) =225a(3) =988a(4) =3065a(5) =7686a(6) =16681a(7) =32600a(8) =58833a(9) =99730a(10) =160721a(11) =248436a(12) =370825a(13) =537278a(14) =758745a(15) =1047856a(16) =1419041a(17) =1888650a(18) =2475073a(19) =3198860a(20) =4082841a(21) =5152246a(22) =6434825a(23) =7960968a(24) =9763825a(25) =11879426a(26) =14346801a(27) =17208100a(28) =20508713a(29) =24297390