The Box-Pierce test is a portmanteau test for whether the first several autocorrelations of a time series are jointly zero. For a series of length , using the first sample autocorrelations , its statistic is
Under the null hypothesis of no autocorrelation, the statistic is approximately chi-squared distributed. The Ljung-Box test modifies the statistic to improve its finite-sample approximation.
More things to try:
Weisstein, Eric W. "Box-Pierce Test." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Box-PierceTest.html