Sorry if the question isn't correct, I'm very new in Objective-C.
I understand why this code throw the Warning: "warning: passing argument 1 of 'initWithObjectsAndKeys:' makes pointer from integer without"

NSDictionary *dictNames =
[[NSDictionary alloc] initWithObjectsAndKeys:
     3, @"",
     4, @"",
     5, @"",nil];

Keys and Values of a NSDictionary must be NSObject and not fundamental types, like the integers 3, 4 and 5. (Correct me if necessary).
But I don't understand why this warning dissapears with the only "correct typing" of the first Key.

NSDictionary *dictNames =
    [[NSDictionary alloc] initWithObjectsAndKeys:
     [NSNumber numberWithInteger:3], @"",
     4, @"",
     5, @"",nil];

It's because NSDictionary assumes the type of the other Keys? Is correct this manner of initialization?