Find a Strobogrammatic number, so if we square it, the result is a pandigit number.
- A Strobogrammatic number is a number when typed on a calculator, and the calculator is spun 180 degrees, the number visually looks the same. (example 6229, 18881)
- A Pandigit number is a number containing the digits 0-9, where each digit appears exactly once. (example 1234567890, 1203456789)
- Because it only has a few possibility, so I tag this puzzle as no-computers.