binomial_coefficient.test

<<< tex
   \mathbf{C}(n,k) = \mathbf{C}_k^n = {}_n\mathbf{C}_k = \binom{n}{k} = \frac{n!}{k!\,(n -k)!}

>>> native
[ EStyled TextNormal [ EStyled TextBold [ EIdentifier "C" ] ]
, ESymbol Open "("
, EIdentifier "n"
, ESymbol Pun ","
, EIdentifier "k"
, ESymbol Close ")"
, ESymbol Rel "="
, ESubsup
    (EStyled TextNormal [ EStyled TextBold [ EIdentifier "C" ] ])
    (EIdentifier "k")
    (EIdentifier "n")
, ESymbol Rel "="
, ESub (EGrouped []) (EIdentifier "n")
, ESub
    (EStyled TextNormal [ EStyled TextBold [ EIdentifier "C" ] ])
    (EIdentifier "k")
, ESymbol Rel "="
, EDelimited
    "("
    ")"
    [ Right (EFraction NoLineFrac (EIdentifier "n") (EIdentifier "k"))
    ]
, ESymbol Rel "="
, EFraction
    NormalFrac
    (EGrouped [ EIdentifier "n" , ESymbol Ord "!" ])
    (EGrouped
       [ EIdentifier "k"
       , ESymbol Ord "!"
       , ESpace (1 % 6)
       , ESymbol Open "("
       , EIdentifier "n"
       , ESymbol Bin "\8722"
       , EIdentifier "k"
       , ESymbol Close ")"
       , ESymbol Ord "!"
       ])
]