a(n) = [x^n] Product_{k=1..2*n} (x + (2*k-1)^2).

A346543

a(n) = [x^n] Product_{k=1..2*n} (x + (2*k-1)^2).

Terms

    a(0) =1a(1) =10a(2) =1974a(3) =1234948a(4) =1601489318

External references