12 lines
461 B
Markdown
12 lines
461 B
Markdown
|
A number chain is created by continuously adding the square of the digits in a number to
|
||
|
|
form a new number until it has been seen before.
|
||
|
|
|
||
|
|
For example,
|
||
|
|
|
||
|
|
44 ? 32 ? 13 ? 10 ? 1 ? 1
|
||
|
|
85 ? 89 ? 145 ? 42 ? 20 ? 4 ? 16 ? 37 ? 58 ? 89
|
||
|
|
|
||
|
|
Therefore any chain that arrives at 1 or 89 will become stuck in an endless loop.
|
||
|
|
What is most amazing is that EVERY starting number will eventually arrive at 1 or 89.
|
||
|
|
|
||
|
|
How many starting numbers below ten million will arrive at 89?
|