>>614 octave
https://ideone.com/50i12U
function c = a(m, n, p)
p(sprintf('A(%d, %d)', m, n));
if m == 0
c = n + 1;
elseif n == 0
c = a(m - 1, 1, p);
else
c = a(m - 1, a(m, n - 1, @(s) p(sprintf('A(%d, %s)', m - 1, s))), p);
end
end
disp(a(2, 1, @disp));