Correction to "Confessional Quick Hits" (March 18), Quick Hit (1)

In my report on the number of ancestors to be examined if one searches one's ancestry back 20 generations, I calculated that the number to be examined was 2 to the 20th power, or 1,048,575 people. That is incorrect – that's only the number of people in the 20th generation. The aggregate number of people to be examined in all generations is (2 to the 20th) + (2 to the 19th) + (2 to the 18th) + . . . . + (2 to the 1st). The actual number of ancestors back to the twentieth generation – counting your parents as the first generation – is 2,097,150.

Your Plainsman apologizes for this gross error.