Number of 3X3 0..n arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric.

A187463

Number of 3X3 0..n arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric.

Terms

    a(0) =26a(1) =1236a(2) =13726a(3) =84048a(4) =325932a(5) =1118854a(6) =2843394a(7) =6976192a(8) =14900828a(9) =30426976a(10) =54176690a(11) =102373984a(12) =165774050a(13) =274508960a(14) =439528372a(15) =685793860a(16) =988022550a(17) =1499573556a(18) =2077344368a(19) =3019161806a(20) =4198346324a(21) =5736736398a(22) =7500683014

External references