Tech@Addebook

Problems in Elementary Number Theory
by Peter Vandendriessche, Hoojo Lee

Excellent collection of challenging problems in elementary number theo (theory (from math. olympiads, various national math. contests, math.math. journals…). Solutions are not presented !

Free download Links

PDF, 425Kb

Direct download:

http://www.problem-solving.be/pen/index.php?f=30
http://rapidshare.com/files/103932549/pen-20070711.pdf.html
http://www.filefactory.com/file/f8fc26/
or djvu
http://www.mediafire.com/?0oveilzn939
http://mihd.net/r1wmdng/

…

Elementary Number Theory A Computational Approach
by William Stein

Free download Links

http://ifile.it/jcm7ha4