a(n) = 8*(10^(2*n+1) - 1)/9 - 4*10^n.A332184a(n) = 8*(10^(2*n+1) - 1)/9 - 4*10^n.Terms a(0) =4a(1) =848a(2) =88488a(3) =8884888a(4) =888848888a(5) =88888488888External referencesoeis: A332184