by Thomas Taylor, A. J. Valpy
Number of pages: 286
Theoretic arithmetic, in three books: containing the substance of all that has been written on this subject by Theo of Smyrna, Nicomachus, Iamblichus, and Boetius, together with some remarkable particulars respecting perfect, amicable, and other numbers, which are not to be found in the writings of any ancient or modern mathematicians. Likewise, a specimen of the manner in which the Pythagoreans philosophized about numbers, and a development of their mystical and theological arithmetic.
Download or read it online for free here:
by Wissam Raji - The Saylor Foundation
These are notes for an undergraduate course in number theory. Proofs of basic theorems are presented in an interesting and comprehensive way that can be read and understood even by non-majors. The exercises broaden the understanding of the concepts.
by Waclaw Sierpinski - ICM
The variety of topics covered here includes divisibility, diophantine equations, prime numbers, the basic arithmetic functions, congruences, the quadratic reciprocity law, expansion of real numbers into decimal fractions, and more.
by Joseph H. Silverman - Pearson Education, Inc.
Introductory undergraduate text designed to entice non-math majors into learning some mathematics, while at the same time teaching them how to think mathematically. The exposition is informal, with a wealth of examples that are analyzed for patterns.
by W W L Chen - Macquarie University
An introduction to the elementary techniques of number theory: division and factorization, arithmetic functions, congruences, quadratic residues, sums of integer squares, elementary prime number theory, Gauss sums and quadratic reciprocity.