a(n) = n^(2n) - (2n)^n.A094647a(n) = n^(2n) - (2n)^n.Terms a(0) =-1a(1) =0a(2) =513a(3) =61440a(4) =9665625a(5) =2173796352a(6) =678117659345External referencesoeis: A094647