a(n) = (2*n-2)*(2*n-1)*a(n-1)+1.A051397a(n) = (2*n-2)*(2*n-1)*a(n-1)+1.Terms a(0) =0a(1) =1a(2) =7a(3) =141a(4) =5923a(5) =426457a(6) =46910271a(7) =7318002277External referencesoeis: A051397