Hi all I've got a feeling this is a really simple question but I can't see it. Explain why p divides (2p-1)! Thanks, Alex
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Originally Posted by alexlbrown59 Hi all I've got a feeling this is a really simple question but I can't see it. Explain why p divides (2p-1)! Thanks, Alex $(2p-1)! = (2p-1)(2p-2)\dots (p+1)(p)(p-1)\dots (2)$ $2p-1>p,~\forall p>1$ so $p$ will appear as a product term in this factorial for $p>1$ $1$ divides everything so it works for $p=1$ as well
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