# File lib/backports/1.9.1/stdlib/prime.rb, line 428
    def next_to(n)
      n = (n-1).div(2)*2+3 # the next odd number to given n
      table_index, integer_index, bit_index = indices(n)
      loop do
        extend_table until @tables.length > table_index
        for j in integer_index...ENTRIES_PER_TABLE
          if !@tables[table_index][j].zero?
            for k in bit_index...BITS_PER_ENTRY
              return NUMS_PER_TABLE*table_index + NUMS_PER_ENTRY*j + 2*k+1 if !@tables[table_index][j][k].zero?
            end
          end
          bit_index = 0
        end
        table_index += 1; integer_index = 0
      end
    end