a(n) = 5*(10^(2*n+1)-1)/9 + 4*10^n.A332159a(n) = 5*(10^(2*n+1)-1)/9 + 4*10^n.Terms a(0) =9a(1) =595a(2) =55955a(3) =5559555a(4) =555595555a(5) =55555955555External referencesoeis: A332159