T(n,k)=1/3 the number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

A184376

T(n,k)=1/3 the number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

Terms

    a(0) =21a(1) =153a(2) =153a(3) =1107a(4) =2755a(5) =1107a(6) =8019a(7) =49235a(8) =49235a(9) =8019a(10) =58077a(11) =880781a(12) =2167173a(13) =880781a(14) =58077a(15) =420633a(16) =15754461a(17) =95528423a(18) =95528423a(19) =15754461a(20) =420633a(21) =3046491a(22) =281803871a(23) =4210059673a(24) =10378244309a(25) =4210059673a(26) =281803871a(27) =3046491a(28) =22064643

External references