Day 289: Geeky Maths Things – Friedman Numbers

Now then, nothing much of interest happened today. So I’m going all geeky on you and introducing you to Friedman numbers. The reason? Why, 289 is a Friedman number – it’s almost like I plan these things (I don’t, I just Google when I struggle to write anything.)

Anyway, Friedman numbers occur an expression using all its own digits in combination with any of the four basic arithmetic operators (+, −, ×, ÷) and sometimes exponentiation can be formed. For example, 25 = 5², while 127 = 2⁷ − 1.

In the case of 289, (8+9)² = 289.

Simple.