1/4 the number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having one or two distinct values.
A211102
1/4 the number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having one or two distinct values.
Terms
- a(0) =10a(1) =184a(2) =6304a(3) =416368a(4) =54050896a(5) =13894956304
External references
- oeis: A211102