Total number of palindromic primes in base 6 below 6^n.

Terms

a(0) =3a(1) =4a(2) =10a(3) =10a(4) =31a(5) =31a(6) =126a(7) =126a(8) =571a(9) =571a(10) =2752a(11) =2752a(12) =14248a(13) =14248a(14) =73971a(15) =73971a(16) =389920a(17) =389920a(18) =2108414a(19) =2108414a(20) =11512078a(21) =11512078