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}

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}

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}

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}

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}