perfect numbers: ie factors sum to original number: 6 1, 2 &3, 28: 1 ,2, 4, 7 & 14. Next is 496, I'll leave you tou check it out. Have a look at wikipedia.
28
Without a sequence given in the question, the next number to 6 is 7.
The next number in the sequence 3-15-6-30-21 is -207.
The next is 3.
The nest number in the sequence is 18. Note that the difference between each number and the next number in the sequence follows the simple sequence of 1,2,3,4. Obviously the next in the sequence of increases is 5, so 13+5=18.
28
35
Without a sequence given in the question, the next number to 6 is 7.
44
The next number in the sequence will be 56.
The next number in the sequence 3-15-6-30-21 is -207.
The next number in the sequence is 20. This is because the sequence is decreasing by 2, then decreasing by 6, then decreasing by 2, and then decreasing by 6. So, the next step would be to decrease by 2 again, resulting in the number 20.
The next is 3.
The nest number in the sequence is 18. Note that the difference between each number and the next number in the sequence follows the simple sequence of 1,2,3,4. Obviously the next in the sequence of increases is 5, so 13+5=18.
19
The next number in the sequence is 18. It's +1, +2, +3, +4, ....
The differences betweent the consequent members are: 48, 24, 12, 6 - the next is equal to the previous divided by two. So the next difference will be 6:2 = 3 and the next member of the sequence will be 10 - 3 = 7