I just told you in the OP. :facepalm:
Well, actually you didn't specifically say how.
Obviously you used the console.
The big question of course is...how did you manage to triple the amount you wanted to spawn. :tongue:
Sounds like you're just lucky your character isn't smeered across the wasteland. As for whether they'll still be around, depends on what they run into. The Behemoths aren't that tough compared to a New Vegas Deathclaw or a swarm of Cazadors. Be one heck of a battle to watch though.