Problem C. 1245. (October 2014)
C. 1245. Consider two consecutive triangular numbers and add one of them to the triple of the other. Prove that the result is also a triangular number.
(5 pont)
Deadline expired on November 10, 2014.
Statistics:
197 students sent a solution. 5 points: 144 students. 4 points: 30 students. 3 points: 7 students. 2 points: 5 students. 1 point: 6 students. 0 point: 5 students.
Problems in Mathematics of KöMaL, October 2014