Number of (n+1)X(n+1) -4..4 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
A211496
Number of (n+1)X(n+1) -4..4 symmetric matrices with every 2X2 subblock having sum zero and one, three or four distinct values.
Terms
- a(0) =29a(1) =105a(2) =385a(3) =1437a(4) =5353a(5) =19901a(6) =73617a(7) =271149a(8) =994593a(9) =3635837a(10) =13253649a(11) =48203469a(12) =174998977a(13) =634413757a(14) =2297355217a(15) =8312124813a(16) =30054882625a(17) =108619779773a(18) =392421136145
External references
- oeis: A211496