Doubly logarithmic tree
Introduction 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 double log treeA similar tree called a k-merger is used in Prokop et al. 's cache oblivious Funnelsort to merge elements.
References
Further reading *M. Frigo, C.E. Leiserson, H. Prokop, and S. Ramachandran. Cache-oblivious algorithms. In ''Proceedings of the 40th IEEE Symposium on Foundations of Computer Science'' (FOCS 99), p. 285-297.1999.Extended abstract at IEEE,  at Citeseer. *Demaine, Erik. Review of the Cache-Oblivious Sorting. Notes for MIT Computer Science 6.897: Advanced Data Structures.