A, B, C and D are triangular numbers.

A, B and C are always consecutive while D is their sum.

Determine (and explain as best as possible¹) how such sets of values are distributed across the number system.

^1. This can be explained in terms of a single variable expression.

(In reply to re(2): an observation by Charlie)

I edited my prior comment to say "only when x is an integer..".

I agree that to find the integers in such a list would be extremely tedious.

Posted by brianjn on 2009-11-30 19:20:52