MathieuCharacteristicExponent[a, q] gives the characteristic exponent r for Mathieu functions with characteristic value a and parameter q.
MathieuCPrime[a, q, z] gives the derivative with respect to z of the even Mathieu function with characteristic value a and parameter q.
MathieuSPrime[a, q, z] gives the derivative with respect to z of the odd Mathieu function with characteristic value a and parameter q.
OverscriptBox[x, y] is the low-level box representation for OverscriptBox[x, y] in notebook expressions.
RamanujanTauTheta[t] gives the Ramanujan tau theta function \[Theta](t).
SphericalBesselJ[n, z] gives the spherical Bessel function of the first kind j_n (z).
SphericalBesselY[n, z] gives the spherical Bessel function of the second kind y_n (z).
SphericalHankelH2[n, z] gives the spherical Hankel function of the second kind h_n^(2)(z).
x_y^z is the low-level box representation for x_y^z in notebook expressions.
WeberE
(Built-in Mathematica Symbol) WeberE[\[Nu], z] gives the Weber function E \[Nu] (z).WeberE[\[Nu], \[Mu], z] gives the associated Weber function E_\[Nu]^\[Mu](z).