vardef bincoeff(expr n, k) =
save ?;
? := (1 for i=(max(k,n-k)+1) upto n: * i endfor )
     / (1 for i=2 upto min(k, n-k): * i endfor); ?
enddef;

def pascaltr expr c =
  string s_;
  for i := 0 upto (c-1):
    s_ := "" for k=0 upto (c-i): & "  " endfor;
    s_ := s_ for k=0 upto i: & decimal(bincoeff(i,k))
             & "  " if bincoeff(i,k)<9: & " " fi endfor;
    message s_;
  endfor
enddef;

pascaltr(4);
end