Combinatorial Functions

ALLCOMB

generates all combinations of $n$ elements taken $k$ at a time

ALLCOMBI

see the ALLCOMB function

ALLPERM

generates all permutations of $n$ elements

COMB

returns the number of combinations of $n$ items taken $r$ at a time

FACT

returns the factorial of an integer

GRAYCODE

returns all subsets in a minimal change order

LCOMB

returns the logarithm of the COMB function

LEXCOMB

returns distinct combinations of $n$ variables taken $k$ at a time in lexicographic order

LEXCOMBI

returns combinations of the indices of $n$ objects taken $k$ at a time in lexicographic order

LEXPERK

returns distinct permutations $n$ variables taken $k$ at a time in lexicographic order

LEXPERM

returns distinct permutations of several variables in lexicographic order

LFACT

returns the logarithm of the FACT (factorial) function

LPERM

returns the logarithm of the PERM function

PERM

returns the number of permutations of $n$ items taken $r$ at a time

RANCOMB

returns random combinations of $n$ elements taken $k$ at a time

RANPERK

randomly permutes the values of the arguments, and returns a permutation of $k$ out of $n$ values

RANPERM

returns random permutations of $n$ elements