a(n) = prime(2^(n-1)*(2*n-1)), n >= 1.

Terms

a(0) =2a(1) =13a(2) =71a(3) =263a(4) =827a(5) =2377a(6) =6379a(7) =16603a(8) =41611a(9) =101573a(10) =243473a(11) =573637a(12) =1333613a(13) =3065983a(14) =6975971a(15) =15746347a(16) =35277211a(17) =78510373a(18) =173717329a(19) =382404863a(20) =837870343a(21) =1828047503a(22) =3973066781a(23) =8604768101a(24) =18576139177a(25) =39983413319