Ramanujan observed that the numbers at the bottom of each group are divisible by 5, that is, 5|p(5n + 4). He also observed that 7|p(7n + 5),11|p(11n + 6), and, on the basis of the very small amount of evidence provided by MacMahon’s table, formulated a very general conjecture, which was essentially correct; the proof was completed by Oliver Atkin in 1967.