a(n) = 3*10^(2*n) + 3*10^n + 1.A177019a(n) = 3*10^(2*n) + 3*10^n + 1.Terms a(0) =7a(1) =331a(2) =30301a(3) =3003001a(4) =300030001a(5) =30000300001External referencesoeis: A177019