The TikZ code of Schulte Table (Tran Le Nam's author):

documentclass[12pt,tikz,border=3mm]{standalone}

usetikzlibrary{calc}

usepackage{xstring}

begin{document}

large

begin{tikzpicture}

defn{5}

defmylist{}

pgfmathsetmacro{numbermax}{n*n}

foreach x in {1,...,numbermax}{ 

    xdefmylist{mylistnoexpand{xnoexpand}}

}

begin{scope} 

pgfmathsetmacro{nt}{n-1}

foreach i in {0,...,nt}

{

    foreach j in {0,...,nt}

    { pgfmathdeclarerandomlist{mynum}{mylist}

        pgfmathrandomitem{mynum}{mynum}

        StrSubstitute{mylist}{{mynum}}{}[sublist]

        globalletmylistsublist 

        pgfmathparse{0.9*rnd+0.3} pgfmathsetmacro{maum}{pgfmathresult}

        pgfmathparse{0.8*rnd} pgfmathsetmacro{mauh}{pgfmathresult}

        definecolor{mau}{rgb}{maum,mauh,0.1}

        node[color=mau] at ($ (i+0.5, j+0.5 ) $) {mynum};

    } 

}

draw (0,0) grid (n,n);

end{scope}

end{tikzpicture}

end{document}

Truly, until now, I don't know about "the random syntax" in any PSTricks documentations. Can I find "the random syntax" in where?

Does not work with xelatex (it doesn't know the random function)

documentclass[12pt]{article}

usepackage{pstricks,pst-calculate,multido}

usepackage{auto-pst-pdf}

definecolorseries{test}{rgb}{step}[rgb]{.95,.85,.55}{.17,.47,.37}

begin{document}



defn{5}

begin{pspicture}(n,n)

psgrid[subgriddiv=0,gridlabels=0pt]

resetcolorseries[25]{test}

multido{rRow=0.5+1.0}{n}{%

  multido{rCol=0.5+1.0}{n}{%

    rput(rCol,rRow){textcolor{test!!+}{pscalculate{randint(1,25)}}}

}}

end{pspicture}



end{document}

And a solution with single random numbers. The random stuff will move into the
pst-math package tomorrow. Then the code will be easier.

documentclass[12pt]{article}

usepackage{pst-calculate}

usepackage{pstricks,multido}



definecolorseries{test}{rgb}{step}[rgb]{.95,.85,.55}{.17,.47,.37}

newcounter{RandNo}setcounter{RandNo}{1}

edefNumbers{pscalculate{randint(1,25)}}



defgetNoList{%

  edefNumber{pscalculate{randint(1,25)}}% Zufallszahl

  addNumber{Number}Numbers!!}

defaddNumber#1#2!!{edefx{noexpandaddNumberA#1;#2}x,,relax}

defaddNumberA#1;#2,#3,#4relax{%

  ifxrelax#2relax % we found new number

  xdefNumbers{Numbers,#1}%

  stepcounter{RandNo}%

  ifnumtheRandNo>25 defnext{}% Neue Zahl?

    else defnext{getNoList}fi%

  else

    ifnum#1=#2 % no new number

      defnext{getNoList}%

    else 

      ifxrelax#3relax 

        defnext{addNumberA#1;,,relax}%

      else %

        defnext{addNumberA#1;#3,#4relax}%

      fi

    fi

  fi

  ifnumtheRandNo<25 next fi

}

defgetRandomNo#1{%

  globalcount0 = 1

  edefx{noexpandgetIndex#1;Numbers,,relax}x}

defgetIndex#1;#2,#3,#4relax{%

  ifnumthecount0=#1 

    defnext{#2}%

  else

    globaladvancecount0 by 1

    defnext{getIndex#1;#3,#4relax}%

  fi

  next

}



begin{document}

defn{5}getNoList

setcounter{RandNo}{1}

begin{pspicture}(n,n)

    psgrid[subgriddiv=0,gridlabels=0pt]

    resetcolorseries[thenumexprn*n]{test}

    multido{rRow=0.5+1.0}{n}{%

        multido{rCol=0.5+1.0}{n}{%

            rput(rCol,rRow){textcolor{test!!+}{getRandomNo{theRandNo}}}%

            stepcounter{RandNo}%

    }}

end{pspicture}



end{document}

A pure PSTricks solution is also possible but we should not reinvent the wheel.

documentclass[12pt,pstricks,border=1pt]{standalone}

usepackage{tikz,xstring}

usetikzlibrary{calc}

defn{5}defmylist{}



pgfmathsetmacro{numbermax}{n*n}

foreach x in {1,...,numbermax}{ 

    xdefmylist{mylistnoexpand{xnoexpand}}

}

pgfmathsetmacro{nt}{n-1}

newpsstyle{gridstyle}{griddots=0,subgriddiv=1}

begin{document}

large

begin{pspicture}[showgrid](n,n)

foreach i in {0,...,nt}

{

    foreach j in {0,...,nt}

    {   pgfmathdeclarerandomlist{mynum}{mylist}

        pgfmathrandomitem{mynum}{mynum}

        StrSubstitute{mylist}{{mynum}}{}[sublist]

        globalletmylistsublist 

        pgfmathparse{0.9*rnd+0.3} pgfmathsetmacro{maum}{pgfmathresult}

        pgfmathparse{0.8*rnd} pgfmathsetmacro{mauh}{pgfmathresult}

        definecolor{mau}{rgb}{maum,mauh,0.1}

        rput(!ispace .5 add jspace .5 add){color{mau}mynum}

    } 

}

end{pspicture}

end{document}

About Pseudo random generator

Rand produces a floating point random number between 0 and 1 inclusive and rand produces a "huge" integer.

documentclass[pstricks,border=12pt,12pt]{standalone}

pstVerb{realtime srand}



begin{document}

begin{pspicture}[showgrid](6,6)

        psLoop{5}{qdisk(!Rand 6 mul Rand 6 mul){!Rand 4 div}}

end{pspicture}

end{document}