MathDB
Putnam 2016 B2

Source:

December 4, 2016
PutnamPutnam 2016

Problem Statement

Define a positive integer nn to be squarish if either nn is itself a perfect square or the distance from nn to the nearest perfect square is a perfect square. For example, 20162016 is squarish, because the nearest perfect square to 20162016 is 452=202545^2=2025 and 20252016=92025-2016=9 is a perfect square. (Of the positive integers between 11 and 10,10, only 66 and 77 are not squarish.)
For a positive integer N,N, let S(N)S(N) be the number of squarish integers between 11 and N,N, inclusive. Find positive constants α\alpha and β\beta such that limNS(N)Nα=β,\lim_{N\to\infty}\frac{S(N)}{N^{\alpha}}=\beta, or show that no such constants exist.