find which number does not belong in this pattern?

Question

1) 1-16-13-11-6

2) 4-8-4-1-3

3) 3-13-8-15-18

choose a number and briefly explain why
i just want to compare my answers.
best answer will be awarded to the best logician

Answer 1

1) 1,16,11, and 6 are all congruent to 1 modulo 5, which means if you divide them by 5 they have a remainder of 1. but 13 ≡ 3 mod 5

2) all but 3 are powers of 2.

3) all but 15 are congruent to 3 mod 5.

Answer 2

1,16,11, and 6 all have remainders of 1 if you try to divide it by 5, but 3 does not have a remainder of 1.

3 is the only number that is not a power of 2. 2^2=4, 2^3=8, 2^0=1, but 3 is not a power of 2 like the other #s.

3, 13, 8 and 18 have remainders of 3 if they are to be divided by 5, but 15 is evenly divisible by 5.

Answer 3

1) 1

2) 1

3) 3

Answer 4

1. 13
2. 3
3. 15