When you enter wrong PIN for multiple times continuously, it should ask for the Gmail account associated with it. So use that Gmail account to reset the pin.
If that didn't work, then we can try to unlock it directly from Samsung Find My Mobile service. This will only work if you have the Find My Mobile option enabled on it. Go to this website --> https://findmymobile.samsung.com/
Login to your Samsung account. Select your device on there. Click More on the right side under Ring My Device, Lock My Device etc. Then click Unlock Device and when you do that, your screen will be unlocked.
Another option is, you can try to setup a new lock using Android Device Manager. Go to this website --> www.google.com/android/devicemanager
Then login to your Google account that you used on your Tab. Click Lock button and setup a new lock. Then use the new lock to unlock the tab. See here --> http://trendblog.net/how-to-bypass-android-phone-lock-screen-pattern-pin-password/
If that didn't work, then the only option to get in to the Tab is factory-reset it. There is no other way to override the PIN screen if the Gmail or Samsung website option didn't work. Factory reset will erase everything from it and return it to new (like Out of Box). This is how they designed the device. Follow the steps below to factory reset it (make sure you follow the steps below exactly or it will not work);
Turn off the Tab
Press and hold down Volume Up, Home and Power buttons at the same time.
When it turns on,release the Power button but continue holding down Volume Up and Home button.
Android system recovery will be loaded now
Select wipedata/factory reset.(Volume buttons to go up or down, select with Power button)
Select Yes — delete all user data.(Volume buttons to go up or down, select with Power button)
Then select reboot system now(Volume buttons to go up or down, select with Power button)
That should factory reset the tab. After factory reset, you need to setup the Tab again (like a new Tab).
If you have any difficulty on following the steps above, please let me know and I will walk you through it.