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Clever counting (Posted on 2015-08-07) Difficulty: 3 of 5
Some positive integers n have the property that the sum
[ n + reverse(n) ] consists entirely of odd (decimal) digits.
For instance, 36 + 63 = 99 and 409 + 904 = 1313.
We will call such numbers reversible; so 36, 63, 409, and 904 are reversible. Leading zeroes are not allowed in either n or reverse(n).
There are 120 reversible numbers below one-thousand.

a. Evaluate how many reversible numbers are there
below 10k, k=2,3... up to 6 or 7 .

b. Analyze the results, aiming to find the relation (i.e. approximate function) between N(k) and k.

Source: Project Euler, modified.

No Solution Yet Submitted by Ady TZIDON    
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  Subject Author Date
re: Part b researched solutionCharlie2015-08-08 08:20:18
Some Thoughtsre(3): part a computer solution wrong?Ady TZIDON2015-08-08 01:52:13
SolutionPart b researched solutionCharlie2015-08-07 23:04:25
re(2): part a computer solution wrong?Charlie2015-08-07 22:27:09
Questionre: part a computer solution wrong?Ady TZIDON2015-08-07 20:37:31
Solutionpart a computer solutionCharlie2015-08-07 18:59:07
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