HasAFactorPastQuadraticModuloAPrime​(AngouriMath.​Functions.​RationalPolynomial)

Whether the resultant has an irreducible factor of degree above two over the rationals,
as seen modulo a prime: a factor over the rationals reduces to factors whose degrees add
up to its own, so one of degree three or more modulo a prime that keeps the degree is one
over the rationals too. Seen, not decided: a factor that splits into linears and
quadratics modulo both primes is left to the factorization. The squarefree decomposition
over the integers is the cost it spares -- a minute for the resultant of
(x^3 + 1)/(x^15 + 2x^2 + 7), of the fifteenth degree and irreducible.