Erlang版的计算Mersenne(LucasLehmer)

-module(mersenne).
-export([run/1,mersenne/1,lucasLehmer_sequence/2]).

lucasLehmer_sequence (0, M) -> 4 rem M;
lucasLehmer_sequence (N, M) when N>0 ->
        erlang:round((math:pow(lucasLehmer_sequence(N-1,M),2)-2)) rem M.

mersenne(N) when N>0 ->
   erlang:round(math:pow(2,N))-1.

lucasLehmer_test(N) ->
   lucasLehmer_sequence(N - 2, mersenne(N)) =:=0.

run(2) ->
    case lucasLehmer_test(2) of
        true ->
                io:format("M(~w) => ~w~n", [2,mersenne(2)]);
        false ->
                1+1
    end;
run(N) ->
    case lucasLehmer_test(N) of
        true ->
                io:format("M(~w) => ~w~n", [N,mersenne(N)]);
        false ->
                1+1
    end,
    run(N-1).