We are given n boxes, labeled 1, 2,..., n. Box i weighs i grams and can support a total weight of i grams. The number of different ways to build a single stack of boxes in which no box will be squashed by the weight of the boxes above it is denoted by f(n). In a 2006 paper, the first author asked for "congruences for f(n) modulo high powers of 2". In this note, we accomplish this task by proving that, for r ≥ 5 and all n ≥ 0, f(2 r n) - f(2 r-1 n) ≡ 0 (mod 2 r ), and that this result is "best possible". Some additional complementary congruence results are also given.
|Original language||English (US)|
|Number of pages||9|
|Journal||Australasian Journal of Combinatorics|
|State||Published - Jun 1 2009|
All Science Journal Classification (ASJC) codes
- Discrete Mathematics and Combinatorics