I am the creator of "Clark's Triangle", which was published in Nov-1978 by NCTM (The National Council of the Teachers of Mathematics, in Reston, Virginia). I have a copy of that publication.
It is kind of an interesting story how it came to be; it started in 7th grade with the realization that the squares of the integers are incremented by each odd integer (immediately realized when the teacher wrote the squares on the chalk board): 0 (+1) (+3) (+5) (+7) (+9) 0 1 4 9 16 25
So, I sought a way to describe the cubes. My original document that I had our local bank notarize shows the original Sigma (summation) equation using recursion.
I would like this added to how "Clark's Triangle" came to be.