[Dayrion]

You need to use SendClientMessage every time a player is an admin.
Check this :

PHP Code:

CMD:admins(playerid,params[])
{
    SendClientMessage(playerid, vert, "___________|- Online Admins -|___________");
    new a;
    foreach(new i : Player) // for(new i=0; i<MAX_PLAYERS; i++)
    {
        if(PlayerInfo[i][pAdminlvl] == 5)
        {
            a = a+1;
             new name[MAX_PLAYER_NAME], str[MAX_PLAYER_NAME+120];
            GetPlayerName(i, name, sizeof(name));
            format(str, sizeof(str), "[Fondateur] » "blancU"%s", name);
            SendClientMessage(playerid, red1, str);
        }
        else if(PlayerInfo[i][pAdminlvl] == 4)
        {
            a = a+1;
             new name[MAX_PLAYER_NAME], str[MAX_PLAYER_NAME+120];
            GetPlayerName(i, name, sizeof(name));
            format(str, sizeof(str), mappeur"[Mappeur] » "blancU"%s", name);
            SendClientMessage(playerid, X11_STEEL_BLUE_2, str);
        }
         else if(PlayerInfo[i][pAdminlvl] == 3)
        {
            new name[MAX_PLAYER_NAME], str[MAX_PLAYER_NAME+120];
            GetPlayerName(i, name, sizeof(name));
            format(str, sizeof(str), "[Admin] » "blancU"%s", name);
            SendClientMessage(playerid, red, str);
            a = a+1;
        }
         else if(PlayerInfo[i][pAdminlvl] > 0)
        {
            new name[MAX_PLAYER_NAME], str[MAX_PLAYER_NAME+120];
            GetPlayerName(i, name, sizeof(name));
            format(str, sizeof(str), modooPs"[Modo] » "blancU"%s", name);
            SendClientMessage(playerid, -1, str);
            a = a+1;
        }
    }
    new str9[120];
    format(str9, sizeof(str9), "There is actually %i connected admins.", a);
    SendClientMessage(playerid, X11_LIGHT_YELLOW_3, str9);
    SendClientMessage(playerid, vert, "|_____________________________________________________|");
    return 1;
} 


If you don't understand, show us your /admins!

EDIT : There is optimized version :

PHP Code:

CMD:admins(playerid,params[])
{
    SendClientMessage(playerid, vert, "___________|- Online Admins -|___________");
    new a, str[MAX_PLAYER_NAME+90];
    foreach(new i : Player) // for(new i=0; i<MAX_PLAYERS; i++)
    {
        switch(PlayerInfo[i][pAdminlvl])
        {
            case 5:
            {
                a++;
                format(str, sizeof(str), "[Fondateur] » "blancU"%s", GetName(i));
                SendClientMessage(playerid, red1, str);
            }
            case 4:
            {
                a++;
                format(str, sizeof(str), mappeur"[Mappeur] » "blancU"%s", GetName(i));
                SendClientMessage(playerid, X11_STEEL_BLUE_2, str);
            }
             case 3:
            {
                format(str, sizeof(str), "[Admin] » "blancU"%s", GetName(i));
                SendClientMessage(playerid, red, str);
                a++;
            }
             case 1,2:
            {
                format(str, sizeof(str), modooPs"[Modo] » "blancU"%s", GetName(i));
                SendClientMessage(playerid, -1, str);
                a++;
            }
        }
    }
    if(a==0) return SendClientMessage(playerid, red1, "There is no admin online");
    format(str, sizeof(str), "There is actually %i connected admins.", a);
    SendClientMessage(playerid, X11_LIGHT_YELLOW_3, str);
    SendClientMessage(playerid, vert, "|_____________________________________________________|");
    return 1;
}