>M=zeros(1000,1000);
>function map A(m,n) ...
$  global M;
$  if m==0 then return n+1; endif;
$  if n==0 then return A(m-1,1); endif;
$  if m<=cols(M) and n<=cols(M) then
$    M[m,n]=A(m-1,A(m,n-1));
$    return M[m,n];
$  else return A(m-1,A(m,n-1));
$  endif;
$endfunction
>shortestformat; A((0:3)',0:5)
         1         2         3         4         5         6
         2         3         4         5         6         7
         3         5         7         9        11        13
         5        13        29        61       125       253