Number of (n+1)X(n+1) -10..10 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
A211819
Number of (n+1)X(n+1) -10..10 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
Terms
- a(0) =189a(1) =1723a(2) =15627a(3) =141649a(4) =1282035a(5) =11589301a(6) =104629731a(7) =943364181a(8) =8493714087a(9) =76361644361a(10) =685449576519
External references
- oeis: A211819