# Math Is Fun Forum

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## #1 2014-04-12 11:53:29

Stangerzv
Member
Registered: 2012-01-30
Posts: 266

### Could be new Prime and there are only 7 found so far.

The equation is given as follows:

Example:

n=1, Ps=1+1=2

n=3, Ps=1-2-3+1*2*3=2

n=5, Ps=1-2-3-4-5+1*2*3*4*5=107

n=6, Ps=1-2-3-4-5-6+1*2*3*4*5*6=701

n=10, Ps=1-2-3-4-5-6-7-8-9-10+1*2*3*4*5*6*7*8*9*10=3628747

n=13, Ps=1-2-3-4-5-6-7-8-9-10-11-12-13+1*2*3*4*5*6*7*8*9*10*11*12*13=6227020711

n=26, Ps=1-2-3-4-5-6-7-8-9-10-11-12-13-..-26+1*2*3*4*5*6*7*8*9*10*11*12*13*..26=403291461126605635583999651

Last edited by Stangerzv (2014-04-12 12:40:17)

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## #2 2014-04-12 12:35:29

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: Could be new Prime and there are only 7 found so far.

Hi Stangerzv;

What is the first equation for?

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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## #3 2014-04-12 12:42:39

Stangerzv
Member
Registered: 2012-01-30
Posts: 266

### Re: Could be new Prime and there are only 7 found so far.

Hi bobbym

Sorry there is a mistake with the minus sign, I've edited it. Basically 1-2-3-..n=2-(1+2+3) and 1*2*..n=n!, the first equation is the generalize equation for the primes.

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## #4 2014-04-12 13:46:35

Stangerzv
Member
Registered: 2012-01-30
Posts: 266

### Re: Could be new Prime and there are only 7 found so far.

Another version of the prime yields 6 primes so far

n=2, Ps=-1+2+1*2=3

n=6, Ps=-1+2+3+4+5+6+1*2*3*4*5*6=739

n=10, Ps=-1+2+3+4+5+6+7+8+9+10+1*2*3*4*5*6*7*8*9*10=3628853

n=14, Ps=-1+2+3+4+5+6+7+8+9+10+11+12+13+14+1*2*3*4*5*6*7*8*9*10*11*12*13*14=87178291303

n=22, Ps=-1+2+3+4+5+6+7+8+9+10+11+12+13+14+..+22+1*2*3*4*5*6*7*8*9*10*11*12*13*14*..*22=1124000727777607680251

n=26, Ps=-1+2+3+4+5+6+7+8+9+10+11+12+13+14+..+26+1*2*3*4*5*6*7*8*9*10*11*12*13*14*..*26=403291461126605635584000349

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## #5 2014-04-12 13:53:29

Stangerzv
Member
Registered: 2012-01-30
Posts: 266

### Re: Could be new Prime and there are only 7 found so far.

There are only three double primes by combining the equations above. The double prime generalize equation is gives as follows:

n=6, Ps=701, 739

n=10, Ps=3628747, 3628853

n=26, Ps=403291461126605635583999651, 403291461126605635584000349

Last edited by Stangerzv (2014-04-12 13:54:25)

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## #6 2014-04-12 18:58:28

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: Could be new Prime and there are only 7 found so far.

Hi;

For the equation:

n = 26 is the highest one for n ≤ 2000

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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## #7 2014-04-13 11:33:48

Stangerzv
Member
Registered: 2012-01-30
Posts: 266

### Re: Could be new Prime and there are only 7 found so far.

Hi bobbym

I have done with the calculation for

n=26 is the highest prime for n ≤ 5000.

Last edited by Stangerzv (2014-04-13 11:34:13)

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## #8 2014-04-13 20:19:30

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: Could be new Prime and there are only 7 found so far.

Hi;

How far have you gone with that one?

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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## #9 2014-04-13 23:43:12

Stangerzv
Member
Registered: 2012-01-30
Posts: 266

### Re: Could be new Prime and there are only 7 found so far.

Hi bobbym

I haven't tried it yet but for

n=26 gives the highest prime for n≤ 8000

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## #10 2014-04-14 02:54:28

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: Could be new Prime and there are only 7 found so far.

Might not be any after n = 26...

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Offline

## #11 2014-04-14 11:34:47

Stangerzv
Member
Registered: 2012-01-30
Posts: 266

### Re: Could be new Prime and there are only 7 found so far.

Hi bobym

For

n=26 gives the highest prime for for n ≤ 4000.

Last edited by Stangerzv (2014-04-14 11:35:06)

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