9. A method comprising: assigning at least one letter in an alphabet to a first digit; assigning at least one other letter in an alphabet to a second digit; accessing a telephone number database storing telephone numbers, each telephone number having a plurality of digits; identifying respective letter combinations created by at least two digits of the respective telephone numbers in the telephone number database; determining whether each of the telephone numbers has digits that occur in any of numeric patterns defined by a first reference list; determining whether the letter combination of each of the telephone numbers forms any of alphanumeric patterns defined by a second reference list, each of the alphanumeric patterns including alphabetic letters or mixed alphabetic letters and numbers; designating those of the telephone numbers that have digits that occur in any of the numeric patterns or whose letter combination forms any of the alphanumeric patterns as patterned telephone 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 and any of the alphanumeric patterns; and designating, by a computing device, the telephone number as a normal number if the telephone number is not designated as one of the patterned telephone numbers.
12. A method as set forth in claim 9 , wherein determining whether the letter combination forms any of the alphanumeric patterns includes: searching the letter combination for sequential letters as defined by the alphabet; and designating the telephone number as the patterned number if the letter combination includes sequential letters.