"Rares spawning again within minutes of despawning"

#PokemonGO: I've searched for topics on this but I'm not sure I'm using the right terms because I can't find much on it. I've noticed on at least three occasions that when something rare spawns, there's a chance it will spawn again in the exact same spot within a few minutes of the last one despawning.The first time it happened was with a Haunter. I caught the first (the last candy needed for a Gengar) and evolved my Gengar on the spot. After doing that, another Haunter suddenly appeared. Chalked it up to coincidence and went on my way.Last week I just barely missed a Venusaur. Was still in the area wondering where to head next, and suddenly another appears! Caught it and praised Helix for a lucky rng.This morning the exact same thing happened with a Blastoise. I was just a few minutes too late, and before I could leave, bam. Now I'm seeing a pattern.Wondering if others have noticed this and what info we may have regarding this? via /r/TheSilphRoad http://ift.tt/2d7KLDj