How do I prevent Drupal from sending an email to the admin every time a new user is created I've inherited maintenance of a drupal 7 site from another group.  Currently, every time a new user account is created the admin is sent an e-mail about it.  The admin wants this disabled.

I've been unable to find what's sending the e-mail.  There's no workflow rule for it, and the Trigger module is disabled.  Admin Notify doesn't have any setting turned on for new users, and visitors do not require admin approval in order to create their accounts.

Some of the research I've done suggests that this is drupal core functionality with no settings attached to it.  If that's the case, how would I go about stopping it?  Any ideas on where else the setting might be for the e-mail?
Do the email sent to the admin have the link to activate the user's account?

If so, go to: example.com/admin/config/people/accounts

Check the REGISTRATION AND CANCELLATION paragraph (should be the 2°): if Visitors, but administrator approval is required is checked, every time a user create an account an email is sent to the admin to let him approve/refuse the user new account.