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 h > 1 {\displaystyle h>1} has 2 2 h − 2 {\displaystyle 2^{2^{h-2}}} children. Each child of the root contains n {\displaystyle {\sqrt {n}}} leaves. The number of children at a node from each leaf to root is 0,2,2,4,16, 256, 65536, ... (sequence A001146 in the OEIS)

A similar tree called a k-merger is used in Prokop et al.'s cache oblivious Funnelsort to merge elements.