Differences of Squares
How many integers $n$ with $1 \le n \le 1000$ can be written as $n = a^2 - b^2$ for some nonnegative integers $a$ and $b$? Give an integer.
Related problems & prerequisites
Worth solving first
- Square Divisors of a Factorial 4.0/10
- Trailing Zeros 3.0/10
Source: Classic exercise in wide circulation; no traceable original source. Statement written for AxiomIQ.