If you stick with the original form of your answer (a recurrance-based one), try Memoizing it, viz.:
But the original form of his answer was not recursive: 
sub fib{
($val0, $val1) =@_;
$sum= $val0 + $val1;
}

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In reply to Re^2: Fibonacci Numbers by blazar
in thread Fibonacci Numbers by dReKurCe

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