Number of (n+1)X(n+1) -6..6 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
A211259
Number of (n+1)X(n+1) -6..6 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
Terms
- a(0) =65a(1) =335a(2) =1703a(3) =8645a(4) =43643a(5) =219333a(6) =1097247a(7) =5465297a(8) =27114351a(9) =134027929a(10) =660336579a(11) =3243840829a(12) =15893481911a(13) =77692754369a(14) =379020868055
External references
- oeis: A211259