How many numbers, from 1 to 50 (both included) can you arrange in a row (one of each) so that each one, except the first and the last, is the sum or difference of its two neighbours?

Example: 3, 10, 7, 17, 24, 41.

10 = 3+7, 7 = 17-10, 17 = 24-7, 24 = 41-17.

(In reply to re: computer solution ---- can you check, please? by pcbouhid)

Yes, the computer gets

66  41  25  16  9  7  2  5  3  8  11  19  30  49  79
79  49  30  19  11  8  3  5  2  7  9  16  25  41  66

as maximal when highNum = 80.

Posted by Charlie on 2008-11-21 00:56:17