Need a regex that accept 10 or 11 digit number and 11 digit input must begin with 1 others should be rejected

Need a regex that accept 10 or 11 digit number and 11 digit input must begin with 1. Any 11 character input that doesn’t begin with 1 should be rejected with Invalid Format error.

Acceptable:
3104825800
13104825800

Not Acceptable:
23104825800