Question 1159309
Cannonballs can be stacked to form a pyramid with a triangular
base. Five of these pyramids are shown below. Find the number
of cannonballs in the 8th pyramid.
a1 equals 1
a2 equals 4
a3 equals 10
a4 equals 20
a5 equals 35
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I haven't tried it, but I don't think you can stack the way the other tutor did.
I think the single cannonball will be on the top.
(JK)