proc sudan(word n, x, y) word:
    word k;
    if n=0 then
        x + y
    elif y=0 then
        x
    else
        k := sudan(n, x, y-1);
        sudan(n-1, k, k+y)
    fi
corp

proc table(word n, xs, ys) void:
    word x, y;
    writeln("sudan(",n,",x,y):");
    write("     ");
    for x from 0 upto xs do write(x:5) od;
    for y from 0 upto ys do
        writeln();
        write(y:4, ":");
        for x from 0 upto xs do write(sudan(n,x,y):5) od;
    od;
    writeln();
    writeln()
corp

proc show(word n, x, y) void:
    writeln("sudan(", n:1, ",", x:3, ",", y:3, ") = ", sudan(n,x,y):5)
corp

proc main() void:
    table(0, 6, 5);
    table(1, 6, 5);
    show(1, 3, 3);
    show(2, 1, 1);
    show(2, 2, 1);
    show(3, 1, 1)
corp