A061414 m.2^n-1 is prime for exactly one coefficient m in the range 0<=m<=n.

8, 9, 19, 23, 25, 26, 34, 39, 58, 64, 66, 68, 82, 83, 84, 86, 108, 109, 117, 118, 128, 129, 130, 134, 136, 150, 151, 175, 176, 178, 179, 194, 197, 227, 231, 234, 240, 241, 248, 258, 259, 275, 276, 278, 281, 309, 315, 316, 317, 330, 331, 332, 336, 337, 339, 340