Number of n-digit base-4 deletable primes.

Terms

a(0) =2a(1) =3a(2) =9a(3) =26a(4) =75a(5) =213a(6) =615a(7) =1853a(8) =5854a(9) =18664a(10) =61248a(11) =205300a(12) =698575a(13) =2409598a(14) =8408050a(15) =29657194a(16) =105628699a(17) =379298191