Patent US 4,665,502

A lottery computer which can select numbers and/or letters randomly and with and without independence between selections. Random numbers are generated independently by having a number of counters run simultaneously for an arbitrary period of time with each counter running at a different repetition rate. Using a high repetition rate compared to the counter running time guarantees randomness. Using separate counters run by separate clocks guarantees independence between selections. Random numbers in which each random selection excludes all other random selections are generated by using a microprocessor which cycles through a loop which contains a complete set of values. After each random selection the random number chosen is removed from the set of values from which a random choice is to be made. A generalized embodiment allows a user to select the alpha or numeric nature of each selection and to set limits on the range of selection. An applications specific embodiment limits a user to a pre-programmed choice of limit on the range of selection and restriction as to the choice of alphabetic or numeric mode.