On certain diophantine equations related to triangular and tetrahedral   numbers
  In this paper we give solutions of certain diophantine equations related to triangular and tetrahedral numbers and propose several problems connected with these numbers.   The material of this paper was presented in part at the 11th International Workshop for Young Mathematicians - NUMBER THEORY, Krak\'{o}w, 14th-20th september 2008. 
Maciej Ulas