Sum of all n-digit Pell numbers.

Terms

a(0) =8a(1) =111a(2) =1562a(3) =8119a(4) =128103a(5) =665857a(6) =10506008a(7) =147830751a(8) =768398401a(9) =12123924128a(10) =63018038201a(11) =994309609247