Coefficient of x^2 in expansion of (x+1) * (x+5) * ... * (x+4*n-3).

A383700

Coefficient of x^2 in expansion of (x+1) * (x+5) * ... * (x+4*n-3).

Terms

    a(0) =0a(1) =0a(2) =1a(3) =15a(4) =254a(5) =5130a(6) =122119a(7) =3365089a(8) =105599276a(9) =3722336388a(10) =145717348221

External references