Pseudosquare

Given an Odd Prime $p$, a Square Number $n$ satisfies $(n/p)=0$ or 1 for all $p<n$, where $(n/p)$ is the Legendre Symbol. A number $n>2$ which satisfies this relationship but is not a Square Number is called a pseudosquare. The only pseudosquares less than $10^8$ are 3 and 6.

See also Square Number