Answer:The first few Thabit numbers are: 2, 5, 11, 23, 47, 95, 191, 383, 767, 1535, 3071, 6143, 12287, 24575, 49151, 98303, 196607, 393215, 786431, 1572863, ...
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Thabit number.
Named after Thābit ibn Qurra
First terms 2, 5, 11, 23, 47, 191, 383, 6143, 786431
Largest known term 3×211,895,718 − 1
OEIS index A007505
Explanation: