1) The phone number, mailing address, or other form of contact information involving digits belonging to a bro, which he may or may not choose to advertise to potential mates.
2) In the context of a dare or a strongly imposed suggestion, may apply to the aformentioned contact information belonging to the desired mate. Only used when imposed upon a bro.
1) "Say, Brantford, can you hook me up with your broman numerals so I can keep in touch about the latest lax scores?"
2) "I dare say, Farnsworth, the odds of you attaining yonder beauty's broman numerals are far inferior to the odds of myself completing the same task."