The number of primes in A013918 less than 10^n.

Terms

a(0) =2a(1) =4a(2) =6a(3) =8a(4) =22a(5) =51a(6) =118a(7) =313a(8) =796a(9) =2022a(10) =5460a(11) =14756a(12) =41508a(13) =116504a(14) =331022a(15) =944930a(16) =2716758a(17) =7851206