Number of 0..4 arrays of length n with each element differing from at least one neighbor by 2 or more, starting with 0.

A221511

Number of 0..4 arrays of length n with each element differing from at least one neighbor by 2 or more, starting with 0.

Terms

    a(0) =0a(1) =3a(2) =7a(3) =36a(4) =130a(5) =532a(6) =2088a(7) =8304a(8) =32876a(9) =130376a(10) =516704a(11) =2048264a(12) =8118864a(13) =32182256a(14) =127565600a(15) =505652480a(16) =2004334368a(17) =7944899296a(18) =31492457536a(19) =124831656000a(20) =494815052864

External references