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

A255661

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

Terms

    a(0) =16a(1) =64a(2) =255a(3) =968a(4) =3340a(5) =10320a(6) =28722a(7) =72920a(8) =171106a(9) =375388a(10) =777452a(11) =1532064a(12) =2891360a(13) =5253680a(14) =9231663a(15) =15745452a(16) =26148180a(17) =42392440a(18) =67248205a(19) =104584680a(20) =159730860a(21) =239932160a(22) =354923400a(23) =517641696a(24) =745106454a(25) =1059497716a(26) =1489468594

External references