InterpolatingPolynomial::moddata
A message is generated because the values in the first argument are inexact numbers:
InterpolatingPolynomial[{1.0, 3.0, 1.0, 2.0, 3.0}, x, Modulus -> 5]This shows valid input to InterpolatingPolynomial:
InterpolatingPolynomial[{1, 3, 1, 2, 3}, x, Modulus -> 5]