Insert the missing number: 15, 31, 63, 127, 255, [?]
Asked Jan 31, 2010
Edited Jan 31, 2010
511. It's times two plus one. 15 x 2 = 30 + 1 = 31 x 2 = 62 + 1 = 63 x 2 = 126 + 1 = 127 x 2 = 254 + 1 = 255 x 2 = 510 + 1 = 511.
Miltiply the number with itself + 1
the answer is 511...(X x 2) +1 = Y