Brilliant Numbers
Tables of maximal and minimal numbers with two, three or four prime factors of the same length (in decimal notation).
Cunningham Project
Current status of the project to factor numbers of the form b^n +/- 1, b = 2, 3, 5, 6, 7, 10, 11, and 12. Maintained by Samuel S. Wagstaff, jr.
Factor Tables
Richard Brent's tables extend the scope of the Cunningham project (factoring b^n+-1) to all applicable bases b less than 100, plus some higher bases.
Factors of Modified Fermat Numbers
Factors of numbers of the form 4^(3^n)+2^(3^n)+1 and 4^(3^n)-2^(3^n)+1.
Factors of Numbers near Googolplex
This table includes all known prime factors of the numbers in the range 10^(10^100) to 10^(10^100)+999, including more than 57000 prime factors of googolplex + 10.