Doubly logarithmic tree
In computer science, a doubly logarithmic tree is a tree where each internal node of height 1, the tree layer above the leaves, has two children, and each internal node of height has children. Each child of the root contains leaves. The number of children at a node from each leaf to root is 0,2,2,4,16, 256, 65536,...
A similar tree called a k-merger is used in Prokop et al.'s cache oblivious Funnelsort to merge elements.