Factor: an integer factorization program for the IBM PC

117. R. P. Brent, Factor: an integer factorization program for the IBM PC, Technical Report TR-CS-89-23, October 1989, 7 pp. (Revised March 1994.)

Abstract: dvi (3K), pdf (76K), ps (27K).

Technical Report: dvi (14K), pdf (101K), ps (57K).

Program and factor database: exe (1582K).


Factor is a program which accesses a large database of factors of integers of the form an + 1. As of October 1989 the database contains more than 30,000 factors of size at least 104. The program Factor implements a simple version of the Elliptic Curve algorithm if it is unable to complete a factorization using trial division and the factor database.

Factor is written in Turbo Pascal and runs on IBM PC or compatible computers. This report describes Factor and various related programs. The programs and the factor database are available as a self-extracting archive.


The program Factor is a convenient way of accessing and updating the factor tables [134]. As of April 2000, the database mentioned in the Abstract has grown to more than 333,000 factors.

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