The ANTS conferences are held every two years and are devoted to algorithmic aspects of number theory, including elementary number theory, algebraic number theory, analytic number theory, geometry of numbers, algebraic geometry, finite fields, cryptography, computational complexity, etc.
The first two ANTS were:
The third ANTS conference will be held this summer at Reed College in Portland, Oregon, USA from Sunday, June 21 to Thursday, June 25, 1998. The proceedings are tentatively scheduled to be Springer LNCS vol. 1423.