For Euclidean distance it seems to be in the neighborhood of (59, 250, 60) which is a bright green, although of course Euclidean distance is not perceptual distance. The blue at (57, 42, 214) also is up there.

oh Id love to add this to the tooling of the color names list. How did you figure out what the largest gap was?

Pick points at random, then use a general-purpose optimization method (the optim function in R) to find local maxima. I don’t claim this is a good way to do it.