Number of Sophie Germain primes between 2^n and 2^(n+1).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =3a(7) =7a(8) =8a(9) =13a(10) =23a(11) =41a(12) =67a(13) =111a(14) =193a(15) =360a(16) =630a(17) =1091a(18) =1938a(19) =3558a(20) =6448a(21) =11876a(22) =21649a(23) =40151a(24) =73658a(25) =135711a(26) =251786a(27) =468678a(28) =875247a(29) =1634069