MathDB
Identical cube arrangements

Source: 2015 BAMO-12 #5

February 22, 2016
geometry3D geometrycube

Problem Statement

We are given nn identical cubes, each of size 1×1×11\times 1\times 1. We arrange all of these nn cubes to produce one or more congruent rectangular solids, and let B(n)B(n) be the number of ways to do this.
For example, if n=12n=12, then one arrangement is twelve 1×1×11\times1\times1 cubes, another is one 3×2×23\times 2\times2 solid, another is three 2×2×12\times 2\times1 solids, another is three 4×1×14\times1\times1 solids, etc. We do not consider, say, 2×2×12\times2\times1 and 1×2×21\times2\times2 to be different; these solids are congruent. You may wish to verify, for example, that B(12)=11B(12) =11.
Find, with proof, the integer mm such that 10m<B(2015100)<10m+110^m<B(2015^{100})<10^{m+1}.