Double recursive relation and normal form

[Christophe Bal]

Hello.

I have the following function on the set of natural.

def B(n):

    if n == 1:

        return 1

    return n * B(n - 1) + n*(n-1)/2*C(n - 1)

def C(n):

    if n == 1:

        return 1

    return n * B(n - 1) + n*(n-1)*C(n - 1)

for k in range(2, 6):

    print C(k)

Can SymPy gives me a normal form if it exists ? 

Christophe BAL

Enseignant de mathématiques en Lycée et développeur Python amateur

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French teacher of math in a high school and amateur Python developer