853 Pisano Periods 1.sf 182 B

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  1. #!/usr/bin/ruby
  2. # Pisano Periods 1
  3. # https://projecteuler.net/problem=853
  4. # Runtime: 0.878s
  5. var n = 120
  6. var limit = 1e9
  7. say n.fib.divisors(limit).grep{ .pisano_period == n }.sum