(A192537)/2.

Terms

a(0) =1a(1) =3a(2) =17a(3) =27a(4) =545a(5) =563a(6) =867a(7) =1395a(8) =1433a(9) =1577a(10) =2187a(11) =580793a(12) =585363a(13) =592433a(14) =593507a(15) =620195a(16) =624945a(17) =632267a(18) =633377a(19) =891075a(20) =921153a(21) =950907a(22) =1481427a(23) =1489217a(24) =1500795a(25) =1502513a(26) =1624913a(27) =1649195