140, answer is 29

來源: 於 2010-07-16 12:53:07 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

140 21, 23, ?, 47, 75, 110

21 + 2X1 = 23
23 + 2X3 = 29
29 + 2X9 = 47
47 + 4X7 = 75
75 + 7X5 = 110