Numbers k such that k*2^m-1 is prime for exactly one exponent m in the range 0<=m<=k.

Terms

a(0) =11a(1) =22a(2) =37a(3) =74a(4) =109a(5) =151a(6) =247a(7) =253a(8) =337a(9) =382a(10) =403a(11) =506a(12) =509a(13) =547a(14) =674a(15) =739a(16) =764a(17) =779a(18) =806a(19) =1325a(20) =1478a(21) =1528a(22) =1558a(23) =1589a(24) =1597a(25) =1612a(26) =1871a(27) =1987a(28) =2263a(29) =2279