The above number is known to many mathematicians and appeared as a solution to a flooble puzzle called “digits 1-9” thus implying that the number is a zeroless pandigital.
The solution showed another feature - this number is also poly-divisible, I.e. as a nine digit number it is divisible by nine, erase the last digit It becomes divisible by 8,…and so on.
There many features connected with our number, but the most important , which I ask you to

PROVE: 381654729 is a Friedman number

Definition and examples @ OEIS A036057
REM: proving does not mean to find somewhere the answer, but to solve it.

Want a hint??

Posted by Ady TZIDON on 2022-07-25 09:51:19