Number of primes less than 10^n containing only the digits 2 and 3 (A020458).

Terms

a(0) =2a(1) =3a(2) =5a(3) =7a(4) =11a(5) =18a(6) =31a(7) =44a(8) =83a(9) =135a(10) =239a(11) =436a(12) =818a(13) =1436a(14) =2773a(15) =4695a(16) =9244a(17) =17022a(18) =32948a(19) =58158a(20) =116040a(21) =214188a(22) =423902a(23) =791950a(24) =1554834a(25) =2904470a(26) =5725780a(27) =10536383a(28) =21070698a(29) =40748211