Catalan (n)
Get n
'th catalan number.
See Planetmath for more information.
Combinations (k,n)
Get all combinations of k numbers from 1 to n as a vector of vectors. (See also NextCombination)
DoubleFactorial (n)
Double factorial: n(n-2)(n-4)...
See Planetmath for more information.
Factorial (n)
Factorial: n(n-1)(n-2)...
See Planetmath for more information.
FallingFactorial (n,k)
Falling factorial: (n)_k = n(n-1)...(n-(k-1))
See Planetmath for more information.
Fibonacci (x)
Aliases: fib
Calculate n
th fibonacci number. That
is the number defined recursively by
Fibonacci(n) = Fibonacci(n-1) + Fibonacci(n-2)
and
Fibonacci(1) = Fibonacci(2) = 1.
See Wikipedia or Planetmath or Mathworld for more information.
FrobeniusNumber (v,arg...)
Calculate the Frobenius number. That is calculate smallest number that cannot be given as a nonnegative integer linear combination of a given vector of nonnegative integers. The vector can be given as separate numbers or a single vector. All the numbers given should have GCD of 1.
See Mathworld for more information.
GaloisMatrix (combining_rule)
Galois matrix given a linear combining rule (a_1*x_+...+a_n*x_n=x_(n+1)).
FrobeniusNumber (n,v)
Find the vector c
of nonnegative integers
such that taking the dot product with v
is
equal to n. If not possible returns null. v
should be given sorted in increasing order and should consist
of nonnegative integers.
See Mathworld for more information.
HarmonicNumber (n,r)
Aliases: HarmonicH
Harmonic Number, the n
'th harmonic number of order r
.
Hofstadter (n)
Hofstadter's function q(n) defined by q(1)=1, q(2)=1, q(n)=q(n-q(n-1))+q(n-q(n-2)).
LinearRecursiveSequence (seed_values,combining_rule,n)
Compute linear recursive sequence using galois stepping.
Multinomial (v,arg...)
Calculate multinomial coefficients. Takes a vector of
k
nonnegative integers and computes the multinomial coefficient.
This corresponds to the coefficient in the homogeneous polynomial
in k
variables with the corresponding powers.
The formula for Multinomial(a,b,c) can be written as:
(a+b+c)! / (a!b!c!)In other words, if we would have only two elements, then Multinomial(a,b) is the same thing as Binomial(a+b,a) or Binomial(a+b,b).
See Planetmath, Mathworld, or Wikipedia for more information.
NextCombination (v,n)
Get combination that would come after v in call to combinations, first combination should be [1:k]. This function is useful if you have many combinations to go through and you don't want to waste memory to store them all.
For example with Combination you would normally write a loop like:
for n in Combinations (4,6) do ( SomeFunction (n) );But with NextCombination you would write something like:
n:=[1:4]; do ( SomeFunction (n) ) while not IsNull(n:=NextCombination(n,6));See also Combinations.
Pascal (i)
Get the Pascal's triangle as a matrix. This will return
an i
+1 by i
+1 lower diagonal
matrix which is the Pascal's triangle after i
iterations.
See Planetmath for more information.
Permutations (k,n)
Get all permutations of k
numbers from 1 to n
as a vector of vectors.
RisingFactorial (n,k)
Aliases: Pochhammer
(Pochhammer) Rising factorial: (n)_k = n(n+1)...(n+(k-1)).
See Planetmath for more information.
StirlingNumberFirst (n,m)
Aliases: StirlingS1
Stirling number of the first kind.
See Planetmath or Mathworld for more information.
StirlingNumberSecond (n,m)
Aliases: StirlingS2
Stirling number of the second kind.
See Planetmath or Mathworld for more information.
Subfactorial (n)
Subfactorial: n! times sum_{k=1}^n (-1)^k/k!.
Triangular (nth)
Calculate the n
'th triangular number.
See Planetmath for more information.
nCr (n,r)
Aliases: Binomial
Calculate combinations, that is, the binomial coefficient.
n
can be any real number.
See Planetmath for more information.
nPr (n,r)
Calculate the number of permutations of size
r
of numbers from 1 to n
.