Given a nonnegative integer \$n\$, determine whether \$n\$ can be expressed as the sum of two square numbers, that is \$\exists a,b\in\mathbb Z\$ such that \$n=a^2+b^2\$.

```
   0 -> truthy
   1 -> truthy
   2 -> truthy
   3 -> falsy
   4 -> truthy
   5 -> truthy
   6 -> falsy
   7 -> falsy
  11 -> falsy
9997 -> truthy
9999 -> falsy

```

Relevant OEIS sequences:

* [A001481](https://oeis.org/A001481 "Truthy") - should return truthy
* [A022544](https://oeis.org/A022544 "Falsy") - should return falsy

This is [code-golf](/questions/tagged/code-golf "show questions tagged 'code-golf'"), so shortest answer as measured in bytes wins.