| (1L << (19 - 2))
              | (1L << (23 - 2))
              | (1L << (29 - 2))
              | (1L << (31 - 2))
              | (1L << (37 - 2))
              | (1L << (41 - 2))
              | (1L << (43 - 2))
              | (1L << (47 - 2))
              | (1L << (53 - 2))
              | (1L << (59 - 2))
              | (1L << (61 - 2));
      // Look up n within the mask.