DouKaku?

-module(leap_year).
-import(lists).
-export([is_leap_year/1]).

list_multiple_of(B,M,[]) ->
    if
        B > M -> [];
        true -> list_multiple_of(B,M,[B])
    end;
list_multiple_of(B,M,L) ->
    C = lists:nth(1,L),
    if
        C + B > M -> L;
        true -> list_multiple_of(B,M,[C + B|L])
    end.

list_leap_year(M) ->
    ((list_multiple_of(4,M,[]) -- list_multiple_of(100,M,[])) ++ list_multiple_of(400,M,[])) -- list_multiple_of(1000,M,[]).

is_leap_year(Y) ->
    length(lists:filter(fun(X) -> X == Y end, list_leap_year(Y))) > 0.