| (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.
      return ((mask >> ((int) n - 2)) & 1) != 0;
    }

    if ((SIEVE_30 & (1 << (n % 30))) != 0) {
      return false;