Number of (n+1)X(n+1) -6..6 symmetric matrices with every 2X2 subblock having sum zero and one or three distinct values.
A211255
Number of (n+1)X(n+1) -6..6 symmetric matrices with every 2X2 subblock having sum zero and one or three distinct values.
Terms
- a(0) =65a(1) =143a(2) =287a(3) =567a(4) =1109a(5) =2145a(6) =4163a(7) =8041a(8) =15609a(9) =30271a(10) =58955a(11) =114925a(12) =224757a(13) =440281a(14) =864529a(15) =1700629a(16) =3351109a(17) =6614459a(18) =13071953a(19) =25871279a(20) =51248961a(21) =101644005a(22) =201725287a(23) =400751925a(24) =796518335a(25) =1584431751a(26) =3152835011
External references
- oeis: A211255