a(n) = 4*(10^(2*n+1)-1)/9 - 3*10^n.A332141a(n) = 4*(10^(2*n+1)-1)/9 - 3*10^n.Terms a(0) =1a(1) =414a(2) =44144a(3) =4441444a(4) =444414444a(5) =44444144444External referencesoeis: A332141