Aliquot - Sequences with initial term up to 10,000, by Christophe Clavier..
Aliquot Sequences - Juan L. Varona's work on aliquot sequences examines sequences with start values up to 10000, and traces them to large composite values..
Aliquot Sequences - Aliquot sequences arise in iterating the sum-of-divisors function s. Bosma has calculated tables up to start value 50,000 and 80 digits..
Aliquot Sequences - Results and software from Paul Zimmermann, addressing the Catalan Conjecture and working on the difficult "Lehmer Five" sequences..
Aliquot Sequences - Statistics by Wolfgang Creyaufmueller, including many tables and links to factoring sites and software..
Amicable Numbers - Observations on amicable pairs and their distribution, including Harshad and Happy Amicable pairs..
Cubes of Perfection - From Ivars Peterson's MathTrek column in MAA Online. Curious relationships satisfied by perfect numbers..
Multiply Perfect Numbers - Up-to-date information on multiperfect numbers and searchable database maintained by Achim Flammenkamp..