excel problem, prime numbers

[mwilliams232]

hey,

does anyone know how to make an excel spreadsheet that inputs any number and in another cell outputs if the number is prime or not. thanks.

-matt w.

 

[Dmitri Harizanov]

dude, I needed the same thing as you, so without all those hard to execute things mentioned previously, see what I was able to figure out:
=IF(ROUND(A1/2,0)=A1/2,"N",IF(ROUND(A1/3,0)=A1/3,"N",IF(ROUND(A1/5,0)=A1/5,"N",IF(ROUND(A1/7,0)=A1/7, "N", "P"))))

basically it returns P if its a prime, and N if it is not.
it works for numbers from 11 to 100, if you need more number than 100, you should add the next primes ( I went from 3 to 7, you will need to add 11, etc ).

hope it helps

P.S. having in mind in Excel you can nest up to 64 times - you should be able to get the "P" or the "N" for all the numbers till 92000 or so - 64th prime number is 307, so 307*307=92000+

 

[jasonb75]

It's hard to believe that there are still people posting on an 8 year old thread and making the task far more complicated than needed.

1 simple array formula can determine if any number below 1048576 (65536 for excel 03 users) is prime or not,

{=IF(SUM(IF(MOD(A1,ROW(INDIRECT("1:"&A1)))=0,1))<=2,"Prime","Not Prime")}

 

[Dmitri Harizanov]

It's hard to believe that there are still people posting on an 8 year old thread and making the task far more complicated than needed.

1 simple array formula can determine if any number below 1048576 (65536 for excel 03 users) is prime or not,

{=IF(SUM(IF(MOD(A1,ROW(INDIRECT("1:"&A1)))=0,1))<=2,"Prime","Not Prime")}

cool, never had time to learn those array formulas...
thanks dude

 

[mortgageman]

dude, I needed the same thing as you, so without all those hard to execute things mentioned previously, see what I was able to figure out:
=IF(ROUND(A1/2,0)=A1/2,"N",IF(ROUND(A1/3,0)=A1/3,"N",IF(ROUND(A1/5,0)=A1/5,"N",IF(ROUND(A1/7,0)=A1/7, "N", "P"))))

basically it returns P if its a prime, and N if it is not.
it works for numbers from 11 to 100, if you need more number than 100, you should add the next primes ( I went from 3 to 7, you will need to add 11, etc ).

hope it helps

P.S. having in mind in Excel you can nest up to 64 times - you should be able to get the "P" or the "N" for all the numbers till 92000 or so - 64th prime number is 307, so 307*307=92000+

If this is a joke - barely funny
If you are serious - I'm speechless

Gene Klein

 

[Dmitri Harizanov]

If this is a joke - barely funny
If you are serious - I'm speechless

Gene Klein

hhheheh, who knows

basically represnts a simple way for doing stuff without fancy formulas... and indeed simply, but time consuming

not all ppl use array formulas... f that need to learn those