Published online by Cambridge University Press: 22 June 2010
Let f∈ℚ[X] and let us consider a Diophantine equation z2=f(x)2±f(y)2. In this paper, we continue the study of the existence of integer solutions of the equation, when the degree of f is 2 and if f(x) is a triangular number or a tetrahedral number.
The first author was supported by the Applied Basic Research Foundation of Sichuan Provincial Science and Technology Department (No. 2009JY0091). The second author thanks Purdue University North Central for the support. The third author was supported by START for young scientists, founded by the Polish Science Foundation.