Hello everyone. I came across this statement and have been looking for a proof. Can anyone help me out? Prove that 1, 6 and 120 are the only numbers which are both triangular and factorials.
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Originally Posted by obinnaokechukwu Hello everyone. I came across this statement and have been looking for a proof. Can anyone help me out? Prove that 1, 6 and 120 are the only numbers which are both triangular and factorials. Here's a clue: the nth triangluar number is given by [tex] \frac{n(n+1)}{2}[\math]
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