IN NATURE of September 9 and October 14 integral right-angled triangles have been discussed. It is of interest to note that in the general solution 2 f g ; f2−g2 ; f2+g2 if we make f and g consecutive terms of the series 1,2,5, 12,29,70 ... where Un = 2 Un−1 + Un−2 we get triangles whose sides about the right angle differ by unity.