Number of (n+1) X (n+1) -7..7 symmetric matrices with every 2 X 2 subblock having sum zero and three or four distinct values.
A211446
Number of (n+1) X (n+1) -7..7 symmetric matrices with every 2 X 2 subblock having sum zero and three or four distinct values.
Terms
- a(0) =90a(1) =548a(2) =3296a(3) =19844a(4) =119260a(5) =716592a(6) =4303756a(7) =25835124a(8) =154970728a(9) =928644692a(10) =5557654436a(11) =33210094112a(12) =198105342332
External references
- oeis: A211446