Wilson primes of order n: Difference between revisions

</pre>

=={{header|FreeBASIC}}==

<lang freebasic>#include "isprime.bas"

function is_wilson( n as uinteger, p as uinteger ) as boolean

'tests if p^2 divides (n-1)!(p-n)! - (-1)^n

'does NOT test the primality of p; do that first before you call this!

'using mods no big nums are required

if p<n then return false

dim as uinteger prod = 1, i, p2 = p^2

for i = 1 to n-1

prod = (prod*i) mod p2

next i

for i = 1 to p-n

prod = (prod*i) mod p2

next i

prod = (p2 + prod - (-1)^n) mod p2

if prod = 0 then return true else return false

end function

print "n: Wilson primes"

print "--------------------"

for n as uinteger = 1 to 11

print using "## ";n;

for p as uinteger = 3 to 10099 step 2

if isprime(p) andalso is_wilson(n, p) then print p;" ";

next p

print

next n

</lang>

{{out}}<pre>

n: Wilson primes

--------------------

1 5 13 563

2 3 11 107 4931

3 7

4

5 5 7 47

6 11

7 17

8

9 541

10 11 1109

11 17 2713