1. A method comprising: storing telephone numbers in a telephone number database; identifying and designating as patterned telephone numbers those of the telephone numbers that have digits that occur in any of numeric patterns defined by a first reference list; identifying and designating as patterned telephone numbers those of the telephone numbers that have digits that occur in any of alphanumeric patterns defined by a second reference list, each of the alphanumeric patterns including alphabetic letters or mixed alphabetic letters and numbers; assigning a weight to each of the patterned telephone numbers, wherein a greater weight is assigned to patterned telephone numbers that have digits that occur both in any of the numeric patterns and in any of the alphanumeric patterns than to patterned telephone numbers that have digits that occur in only one of any of the numeric patterns or any of the alphanumeric patterns; and designating, by a computing device, any remaining telephone numbers in the telephone number database as normal telephone numbers.