a(n) = prime(2^(n + 1)) - prime(2^n).

Terms

a(0) =1a(1) =4a(2) =12a(3) =34a(4) =78a(5) =180a(6) =408a(7) =900a(8) =2052a(9) =4490a(10) =9702a(11) =21010a(12) =45144a(13) =96486a(14) =205590a(15) =435548a(16) =920896a(17) =1938594a(18) =4072946a(19) =8535970a(20) =17845982a(21) =37242540a(22) =77569570a(23) =161300102a(24) =334906956a(25) =694329000a(26) =1437620932a(27) =2972973918a(28) =6141189354a(29) =12672042908