Semiprimes p*q such that q = p + 2^k for some k >= 0.

Terms

a(0) =6a(1) =15a(2) =21a(3) =33a(4) =35a(5) =57a(6) =65a(7) =77a(8) =143a(9) =161a(10) =185a(11) =201a(12) =209a(13) =221a(14) =323a(15) =377a(16) =393a(17) =437a(18) =473a(19) =497a(20) =713a(21) =899a(22) =1073a(23) =1457a(24) =1517a(25) =1529a(26) =1577a(27) =1763a(28) =1769a(29) =1841