> (2 5 11 23 47 97 197 397 797 1597 3203 6421 12853 25717 51437 > 102877 205759 > 411527 823117 1646237 3292489 6584983 13169977 26339969 52679969 > 105359939 > 210719881 421439783 842879579 1685759167 3371518343) > * (length *) > 31 You rule; I was just about to write this same snippet. Thanks. ~ j.