Number of n-digit base-7 deletable primes.

Terms

a(0) =3a(1) =7a(2) =21a(3) =59a(4) =184a(5) =534a(6) =1620a(7) =4889a(8) =15607a(9) =50138a(10) =165569a(11) =551580a(12) =1860565a(13) =6345080