403, 806, 1209, 1612 +403 . . .
Any of its factors which are 1, 13, 31 and itself 403
The next number in the sequence 5-7-13-31 is 69.
1 and 31 (31 is a Prime number).
Nothing goes into 13 evenly other than 1 and 13, so that means it is a prime number.
13/4 = 31/4
13 over 4 as a mixed number = 31/4
13 over 4 as a mixed number = 31/4
The mixed number for 13 over 4 = 31/4
31 (3*4+1 = 13)
it is: 22
31, 40 1st, 3rd, etc go up by 4, others by 9
31 Because, twice 31 is 62. And, 62 plus 13 is 75.