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
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form a new number until it has been seen before.
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For example,
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44 ? 32 ? 13 ? 10 ? 1 ? 1
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85 ? 89 ? 145 ? 42 ? 20 ? 4 ? 16 ? 37 ? 58 ? 89
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Therefore any chain that arrives at 1 or 89 will become stuck in an endless loop.
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What is most amazing is that EVERY starting number will eventually arrive at 1 or 89.
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How many starting numbers below ten million will arrive at 89? |