Number of 4k+1 primes (A002144) in range ]2^n,2^(n+1)].

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =4a(5) =6a(6) =10a(7) =21a(8) =38a(9) =66a(10) =127a(11) =233a(12) =432a(13) =805a(14) =1511a(15) =2837a(16) =5378a(17) =10186a(18) =19294a(19) =36827a(20) =70157a(21) =133975a(22) =256852a(23) =492882a(24) =946848a(25) =1823129a(26) =3513599a(27) =6780412a(28) =13103462a(29) =25348870