the Golden section, and string" dept.physics.upenn.edu/courses/gladney/mathphys/Contents.html : "The Interactive Textbook for Mathematics, Physics, and Chemistry" was put up in 1994 and assumes extensive use of Maple , but is still good. research.att.com/~njas/sequences : "On-Line Encyclopedia ofInteger Sequences. Type in a series of numbers and the database willcomplete the sequence and provide