They are:
1x40, 2x20, 4x10, 5x8 are all the factor pairs of 40.
The factor pairs of 20 are: 20,1 / 10,2 / 5,4
The factor pairs for 38 are (1, 19) and (2, 38).
The factor pairs of 26 are: 1 × 26 2 × 13
53,1
1,3,149,447
612,1306,2204,3153,4102,668,951,1236,1734,18
57,119,3
1,81,3,27,9
51,117,3
164,182,241,4
They are:200,1100,250,440,525,820,10