I translated the original Hyakugojuuichi. Hopefully, it's accurate.

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When it comes to all of your friends
More would be better!
It's clear the most you can have is
151!
With courage, you can be certain
You'll get friends!
However, it's only sometimes
You will be heart broken
Friends might run away!

*Chorus*
I'll remember meeting you guys
Whatever was hurt is hurt
Um, I forgot about that

There is more
Definitely somewhere
My friends should be here
151 Joys
151 Dreams
151 Memories
Let's aim for that!