#!/usr/bin/ruby
yprev = nil
for year in 1900..2200
  t = Time.gm(year, 11, 4, 0, 0, 0)
  next unless 'Sat' == t.strftime('%a')
  ydif = year - yprev.to_i
  printf("%4u %2u\n", year, ydif) if yprev
  yprev = year
end