Determine the maximum value of a (base ten) positive integer N (with non leading zeroes) such that each of the digits of N, with the exception of the first digit and the last digit, is less than the arithmetic mean of the two neighboring digits.

Note: Try to solve this problem analytically, although computer program/ spreadsheet solutions are welcome.

(In reply to re: Solution by Charlie)

Thanks Charlie.  Had created the list without the aid of spreadsheet or program.  After your comment, I created a short program to find all that I had missed. It should be correct now.

Posted by Dej Mar on 2008-09-28 07:54:40