How do I translate "rec" from MuPAD to MATLAB Symbolic Math Toolbox?

If I use "convertMuPADNotebook" on a MuPAD file that contains the rec command, such as

rec(y(n + 2) = y(n + 1) + 4*y(n), y(n))

I see

%CODE TRANSLATION ISSUE 1 - aux1
%ERROR : Unable to translate calls to the function 'rec'.
aux1 = 'aux1Untranslated' % MuPAD code: rec(y(n + 2) = y(n + 1) + 4*y(n), y(n))

In the translated file.

Answer 1

[MathWorks Support Team]

Currently "convertMuPADNotebook" does not translate "rec" from MuPAD to MATLAB. This issue has been reported to development and may change in a future release. To achieve this workflow use 

syms y(n) z
assume(n>=0 & in(n, 'integer'))
f = y(n+2) - y(n+1) - 4 * y(n)

fZT = ztrans(f,n,z)

syms yZT
fZT = subs(fZT,ztrans(y(n),n,z),yZT)

yZT = solve(fZT, yZT)

ySol = iztrans(yZT,z,n);
ySol = simplify(ySol)

ySol1 = simplify(subs(ySol,[y(0) y(1)], [0 1]))

As per the "ztrans" documentation: https://www.mathworks.com/help/releases/R2022a/symbolic/compute-z-transforms-and-inverse-z-transforms.html