Journal: Username is not available -- says Gmail -- but neither is it t

After inability to register a desired username at Gmail, I settled with an alternative. But in years passed I haven't stopped wondering why I can register this screen name with every service, but Gmail.

1. Certain male names with prefix 'f1' cannot be registered with Gmail. One would assume they're taken, but they aren't. We've sent test emails to these accounts, but we get back "This Gmail user does not exist". Examples: f1rich, f1richard, f1robert, f1alexander, f1nate, f1sasha.

2. Female name with prefix 'f1' can easily be registered and marked as available in ajaxy registration form. Examples: f1sally, f1catherine, f1becky, f1molly, f1britney.

3. If you swap 'f1' with 'f2' for male names, names become available.

Why would Google keep these usernames reserved?