How it is calculated
The exponent is not a fixed 3. It is how many digits that particular number has. 153 has three digits, so the powers are cubes.
Sum = d1^k + d2^k + … , k is the number of digits
Where the numbers come from
- Number
Example
153 = 1³ + 5³ + 3³. That is an Armstrong number.
Questions
Do single-digit numbers work?
Yes: a digit to the power of 1 equals itself.
What if the sum does not match?
The number is not an Armstrong number. The sum is still shown.
Zero?
0^1 = 0, so zero is allowed.