D20G
A
A
A single number, such as 21357, does not define a sequence.
The sequence "rygb" represents the first letters of the colors in the rainbow: red, yellow, green, and blue. The next color in the sequence is indigo, which starts with the letter "i." Therefore, the next letter in the sequence is "i."
456789
A
A
A single number, such as 21357, does not define a sequence.
p
It is: Y
K
Check out the link for the sequence.
h o n
040608
L
k comes next, and then l.
A single number, such as 2481020, cannot define a sequence.