Where did this puzzle come from? I may be wrong, but I think there's a typo in it, perhaps two. First I believe the lower left number in the 4th pyramid should be 10, not 1. This would make the pattern for the lower left numbers 1, 3, 6, 10, 15, which is a pretty simple sequence. With that change the center number of each pyramid is 2 times the sum of the three outer numbers, but with one exception: following this rule the middle number of the second pyramid should be 18, not 1. And the missing number is then 2(9+15+81) = 210. I realize that the probability of having two typos in this puzzle is small, but it's something to consider.