# A059990 (b-file synthesized from sequence entry) 1 1 2 1 3 7 4 5 5 31 6 7 7 127 8 85 9 511 10 341 11 2047 12 455 13 8191 14 5461 15 32767 16 21845 17 131071 18 9709 19 524287 20 349525 21 2097151 22 1398101 23 8388607 24 1864135 25 33554431 26 22369621 27 134217727 28 89478485 29 536870911 30 119304647