Numbers of n-digit primes that undulate.

Terms

a(0) =4a(1) =20a(2) =74a(3) =347a(4) =1743a(5) =8385a(6) =44355a(7) =229952a(8) =1235489a(9) =6629026a(10) =37152645a(11) =202017712a(12) =1142393492a(13) =6333190658