The perfect numbers are found in at least three groups of numbers as described below. The results of these findings are quite remarkable, as seen towards the end.
The first triangular numbers: 1, 3, (6), 10, 15, 21, (28), 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210, 231, 253, 276...