Constant term in the expansion of (1+x+y+1/x+1/y)^n without assuming commutativity.

A328494

Constant term in the expansion of (1+x+y+1/x+1/y)^n without assuming commutativity.

Terms

    a(0) =1a(1) =1a(2) =5a(3) =13a(4) =53a(5) =181a(6) =713a(7) =2689a(8) =10661a(9) =41989a(10) =168785a(11) =680329a(12) =2770409a(13) =11331529a(14) =46639157a(15) =192762013a(16) =800228069a(17) =3333843685a(18) =13936599857a(19) =58432259977a(20) =245665962113

External references