3, 7, 15, 39, 63, 127, 255, 511?

More Questions from Odd Man Out and Series

• 40960, 10240, 2560, 640, 200, 40, 10?
• 1, 1, 2, 6, 24, 96, 720?
• Find out the wrong number in the series 5, 15, 30, 135, 405, 1215, 3645?
• 2, 5, 10, 17, 26, 37, 50, 64?
• 331, 482, 551, 263, 383, 242, 111?
• 1, 2, 6, 15, 31, 56, 91?
• 25, 36, 49, 81, 121, 169, 225?
• 56, 72, 90, 110, 132, 150?
• 6, 13, 18, 25, 30, 37, 40?
• 46080, 3840, 384, 48, 24, 2, 1?

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