foreach (1..10) { print fibo($_), "\n" }

sub fibo {
  $_ = '1'.'2'x($_[0]).'1';

  while (/[1568]$/)
    {s=([2-589]?[01358])=int(abs((67*$1-1467)*$1+1423)/140)=eg}
  y/02678//d;
  return length
}