Hint to puzzle 121: Integer sequence
Letting a1 = x, a2 = y, and a3 = z, show that a6 = z2(z + y)(y + x)(y + x + 1).
Set a6 = 8820, noting that two of the factors of a6 are consecutive.
Letting a1 = x, a2 = y, and a3 = z, show that a6 = z2(z + y)(y + x)(y + x + 1).
Set a6 = 8820, noting that two of the factors of a6 are consecutive.