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<p>of  divided by the <a href="page.php?w=factorial">factorial</a> of 3:<br/>
:</p>

<p>The tetrahedral numbers can also be represented as <a href="page.php?w=binomial_coefficient">binomial coefficient</a>s:<br/>
:Tetrahedral numbers can therefore be found in the fourth position either from left or right in <a href="page.php?w=Pascal%27s_triangle">Pascal's triangle</a>.</p>

<p><big>Proofs of formula</big></p>
<p>This proof uses the fact that the th triangular number is given by<br/>
:It proceeds by <a href="page.php?w=Mathematical_induction">induction</a>.</p><p>
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