Number of (n+1)X(n+1) -7..7 symmetric matrices with every 2X2 subblock having sum zero and two, three or four distinct values.
A211448
Number of (n+1)X(n+1) -7..7 symmetric matrices with every 2X2 subblock having sum zero and two, three or four distinct values.
Terms
- a(0) =112a(1) =842a(2) =6350a(3) =48066a(4) =365098a(5) =2782326a(6) =21268302a(7) =163031330a(8) =1252859362a(9) =9649453790a(10) =74464405550a(11) =575598981066
External references
- oeis: A211448