Triangular array, read by rows: T(n,k) = [(x*y)^k] (-1 + (1 + x + 1/x)*(1 + y + 1/y))^n for -n <= k <= n.
A329816
Triangular array, read by rows: T(n,k) = [(x*y)^k] (-1 + (1 + x + 1/x)*(1 + y + 1/y))^n for -n <= k <= n.
Terms
- a(0) =1a(1) =1a(2) =0a(3) =1a(4) =1a(5) =2a(6) =8a(7) =2a(8) =1a(9) =1a(10) =6a(11) =27a(12) =24a(13) =27a(14) =6a(15) =1a(16) =1a(17) =12a(18) =70a(19) =132a(20) =216a(21) =132a(22) =70a(23) =12a(24) =1a(25) =1a(26) =20a(27) =155a(28) =480a(29) =1070
External references
- oeis: A329816