Number of (n+1)X(n+1) -5..5 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
A211335
Number of (n+1)X(n+1) -5..5 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
Terms
- a(0) =47a(1) =203a(2) =851a(3) =3551a(4) =14747a(5) =61279a(6) =255139a(7) =1066031a(8) =4472467a(9) =18846943a(10) =79770595a(11) =339053711a(12) =1446716915a(13) =6194800095a(14) =26609084003a(15) =114610153487a(16) =494820389939
External references
- oeis: A211335