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## Power sum in Ruby

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$1^m + 2^m + \ldots + n^m = ?$

It is not easy to calculate if n is 50, nad m is 9. Here Ruby comes for help. If you had already installed Ruby 1.8 or Ruby 1.9, open terminal (in Linux) type irb and press enter. Then type following (don’t type > sign) :

```>sum(n,m)
>return 1 if n == 1
>sum(n-1,m) + n^m if n > 1
>end```

It is all, now type sum(50,9) and you will get the answer…