Is there UB for n = 4?

[DimaTomsk]

sport-programming-library/Math/divisibility.cpp

Line 18 in 2aa95b2

std::vector<T> res(cbrt(n) + 1);

[Tnirpps]

We really appreciate you reporting this — you are absolutely right, this is indeed a bug!
For cases like n = 4, the initial allocation can be too small, which may lead to out-of-bounds writes and undefined behavior. We’ll fix it.