a(n) = A084605(n)^2, the square of the central coefficient in (1 + x + 4*x^2)^n.

A322240

a(n) = A084605(n)^2, the square of the central coefficient in (1 + x + 4*x^2)^n.

Terms

    a(0) =1a(1) =1a(2) =81a(3) =625a(4) =21025a(5) =314721a(6) =8071281a(7) =155975121a(8) =3685097025a(9) =79065004225

External references