a(n) = A004001(10^n).

Terms

a(0) =1a(1) =6a(2) =57a(3) =510a(4) =5373a(5) =53505a(6) =510403a(7) =5247173a(8) =52736107a(9) =511172800a(10) =5189628970a(11) =52334438874a(12) =511861449132