How to indicate change without change?

I'm having trouble putting the problem into words but hopefully this makes sense.

For a game I'm making (for a stats class project) I made a custom random number displayer. You click to get a new number. (link here)

The problem now is that duplicate random numbers are allowed and are actually quite common. Every time I get a duplicate random number, it feels like I just misclicked.

Things I tried to remedy this problem:

• Flashing pink every time a new number came up to indicate a new number (link)
• Sliding the number in from the left to indicate a new number (link)
• Flashing the text white (link)

but these seem too obnoxious.

It also needs to be quick (so no long fades or badges) because I need to generate numbers at up to about 1 number/sec. I would also like to keep it simple because I don't want to learn jQuery just for this thing.

So how do I indicate that a new random number is being displayed even when it is the same random number? I put a little counter at the bottom left corner for now, but it's too unnoticeable.

Again, sorry for my poor language and bad knowledge of UX. This is my first time designing something for anyone other than myself.