T(n,k)=Number of length n+k 0..2 arrays with at most two downsteps in every k consecutive neighbor pairs.

A255622

T(n,k)=Number of length n+k 0..2 arrays with at most two downsteps in every k consecutive neighbor pairs.

Terms

    a(0) =9a(1) =27a(2) =27a(3) =81a(4) =81a(5) =81a(6) =237a(7) =243a(8) =243a(9) =243a(10) =651a(11) =694a(12) =729a(13) =729a(14) =729a(15) =1647a(16) =1803a(17) =2040a(18) =2187a(19) =2187a(20) =2187a(21) =3834a(22) =4248a(23) =5088a(24) =5997a(25) =6561a(26) =6561a(27) =6561a(28) =8272a(29) =9186

External references