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Re: bug in Mathematica?

• To: mathgroup at smc.vnet.net
• Subject: [mg122676] Re: bug in Mathematica?
• From: "Dr. Wolfgang Hintze" <weh at snafu.de>
• Date: Sat, 5 Nov 2011 04:48:33 -0500 (EST)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <j90hep$sp5$1@smc.vnet.net>

"Hansruedi Widmer" <widmer at baden.ch> schrieb im Newsbeitrag 
news:j90hep$sp5$1 at smc.vnet.net...
> Hi Everyone
>
>
> The code
>
> Sum[Binomial[m, j], {j, 1, m - 1}]
>
> produces the correct value -2+2^m.
>
>
> But the code
>
> Product[Binomial[m, j], {j, 1, m - 1}]
>
> creates the wrong value of zero. Does anyone have an explanation for 
> why
> this is happening?
>
>
> Thanks and best regards
>
> Hansrued Widmer
>
>
>
>
I don't see a zero, my version simply does not evaluate the product in 
symbolic form.
But the values are ok:
(Product[Binomial[#1, j], {j, 1, #1 - 1}] & ) /@ Range[10]

{1, 2, 9, 96, 2500, 162000, 26471025, 11014635520,
11759522374656, 32406091200000000}

Hope this helps
Best regards,
Wolfgang