Number of (n+1)X(n+1) -7..7 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
A211447
Number of (n+1)X(n+1) -7..7 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
Terms
- a(0) =91a(1) =561a(2) =3397a(3) =20495a(4) =123133a(5) =738307a(6) =4420961a(7) =26449067a(8) =158114037a(9) =944443595a(10) =5635861085a(11) =33592371427a(12) =199953831841
External references
- oeis: A211447