Number of (n+1)X(n+1) -11..11 symmetric matrices with every 2X2 subblock having sum zero and three or four distinct values.
A211716
Number of (n+1)X(n+1) -11..11 symmetric matrices with every 2X2 subblock having sum zero and three or four distinct values.
Terms
- a(0) =230a(1) =2312a(2) =23056a(3) =228984a(4) =2263896a(5) =22292220a(6) =218675604a(7) =2137539096a(8) =20825437008a(9) =202270208796
External references
- oeis: A211716