We evaluate the number u(n) of length-n finite sequences (ak)1≤k≤n of natural numbers that satisfy the inequality ak ≤ k2 for all k. We thus determine two recurrence relations for u(n) by two different methods, and we give an explicit expression in closed form for it.
|Original language||English (US)|
|Journal||Journal of Integer Sequences|
|State||Published - Jan 13 2015|
All Science Journal Classification (ASJC) codes
- Discrete Mathematics and Combinatorics