a(n) = 4*(10^(2*n+1)-1)/9 - 2*10^n.A332142a(n) = 4*(10^(2*n+1)-1)/9 - 2*10^n.Terms a(0) =2a(1) =424a(2) =44244a(3) =4442444a(4) =444424444a(5) =44444244444External referencesoeis: A332142