T(n,k)=1/25 the number of (n+1)X(k+1) 0..4 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements.

A203656

T(n,k)=1/25 the number of (n+1)X(k+1) 0..4 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements.

Terms

    a(0) =9a(1) =81a(2) =81a(3) =729a(4) =1517a(5) =729a(6) =6561a(7) =28057a(8) =28057a(9) =6561a(10) =59049a(11) =519445a(12) =1116249a(13) =519445a(14) =59049a(15) =531441a(16) =9616161a(17) =44577561a(18) =44577561a(19) =9616161a(20) =531441a(21) =4782969a(22) =178019197a(23) =1780968921a(24) =3906948333a(25) =1780968921a(26) =178019197a(27) =4782969a(28) =43046721a(29) =3295578857

External references