Primality by Wilson's theorem: Difference between revisions

=={{header|Erlang}}==

<lang Erlang>

#! /usr/bin/escript

isprime(N) when N < 2 -> false;

isprime(N) -> fac_mod(N - 1, N) =:= N - 1.

fac_mod(N, M) -> fac_mod(N, M, 1).

fac_mod(1, _, A) -> A;

fac_mod(N, M, A) -> fac_mod(N - 1, M, A*N rem M).

main(_) ->

io:format("The first few primes (via Wilson's theorem) are: ~n~p~n",

[[K || K <- lists:seq(1, 128), isprime(K)]]).

</lang>

{{Out}}

<pre>

The first few primes (via Wilson's theorem) are:

[2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,

103,107,109,113,127]

</pre>