a(n) is the constant term in the expansion of (1 + (1+x)*(1+y) + (1+1/x)*(1+1/y) + (1+1/x^2)*(1+1/y^2))^n.
A327994
a(n) is the constant term in the expansion of (1 + (1+x)*(1+y) + (1+1/x)*(1+1/y) + (1+1/x^2)*(1+1/y^2))^n.
Terms
- a(0) =1a(1) =4a(2) =22a(3) =157a(4) =1342a(5) =12694a(6) =126601a(7) =1301353a(8) =13647622a(9) =145280776a(10) =1564974682a(11) =17022150688a(12) =186647326849
External references
- oeis: A327994