LegendreP[n, x] gives the Legendre polynomial P_n (x). LegendreP[n, m, x] gives the associated Legendre polynomial P_n^m(x).
LucasL
(Built-in Mathematica Symbol) LucasL[n] gives the Lucas number L_n.LucasL[n, x] gives the Lucas polynomial L_n (x).
QPochhammer[a, q, n] gives the q-Pochhammer symbol (a; q) n.QPochhammer[a, q] gives the q-Pochhammer symbol (a; q) \[Infinity].QPochhammer[q] gives the q-Pochhammer symbol ...
SinIntegral[z] gives the sine integral function Si(z).
CopyToClipboard[expr] replaces the contents of the clipboard with expr.
E
(Built-in Mathematica Symbol) E is the exponential constant E (base of natural logarithms), with numerical value \[TildeEqual] 2.71828.
ExpressionCell[expr] gives an expression cell that can appear in a Mathematica notebook. ExpressionCell[expr, " style"] gives an expression cell with the specified style.
And
(Built-in Mathematica Symbol) e_1 && e_2 && ... is the logical AND function. It evaluates its arguments in order, giving False immediately if any of them are False, and True if they are all True.
ArcCosh
(Built-in Mathematica Symbol) ArcCosh[z] gives the inverse hyperbolic cosine cosh -1 (z) of the complex number z.
ArithmeticGeometricMean[a, b] gives the arithmetic-geometric mean of a and b.