Number of (n+1)X(n+1) -10..10 symmetric matrices with every 2X2 subblock having sum zero and three or four distinct values.
A211818
Number of (n+1)X(n+1) -10..10 symmetric matrices with every 2X2 subblock having sum zero and three or four distinct values.
Terms
- a(0) =188a(1) =1702a(2) =15334a(3) =138130a(4) =1242978a(5) =11177174a(6) =100431854a(7) =901725738a(8) =8089235074a(9) =72498715894a(10) =649077462926
External references
- oeis: A211818