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**pellerinb****Member**- Registered: 2012-12-26
- Posts: 43

Just curious if anyone else has observed this. I have found it true up to N = 1 million.

GCD(sum_(i=1 to N) i!, sum_(i=1 to N+1) i!) = 99 for N >= 10

I'm thinking it might be easy to prove this too... I'm not sure though.

Prime numbers have got to be the neatest things; they are like atoms. Composites are two or more primes held together by multiplication.

In biology, we use math like we know what we are talking about. Sad isn't it.

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The question seems interesting, could you please make it clear with latex?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

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**pellerinb****Member**- Registered: 2012-12-26
- Posts: 43

I don't know how to input latex into this forum but I can tell you that if you enter 'sum_(i=1)^10 i! ; sum_(i=1)^11 i!' without quotes into the Wolfram|Alpha website or iPhone/iPad app, you will see the desired equations and their GCD.

Prime numbers have got to be the neatest things; they are like atoms. Composites are two or more primes held together by multiplication.

In biology, we use math like we know what we are talking about. Sad isn't it.

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**muxdemux****Member**- Registered: 2012-12-23
- Posts: 80

Latex here:

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