Number of Fermat pseudoprimes to base 3 less than 2^n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =2a(7) =2a(8) =3a(9) =6a(10) =10a(11) =17a(12) =21a(13) =30a(14) =44a(15) =61a(16) =87a(17) =124a(18) =175a(19) =254a(20) =362a(21) =511a(22) =696a(23) =955a(24) =1313a(25) =1802a(26) =2462a(27) =3321a(28) =4422a(29) =5969