This is an alternating series in alphabetical order. The middle letters follow the order ABCDE. The first and third letters are alphabetical beginning with J. The third letter is repeated as a first letter in each subsequent three-letter segment.

Because the letters are the same, concentrate
on the number series, which is a simple 2, 3,
4, 5, 6 series, and follows each letter in
order.

The first two letters, PQ, are static. The
third letter is in alphabetical order, beginning with R. The number series is in
descending order beginning with 5.

The letters are consecutive letters with the prime number as the position value and the digits on either of the letter together indicate the place value of the letter.2W3 => W = 231S9 => S = 191Q7 => Q = 171K1 => K = 11Missing term is 1M3

Each letter of the first group is moved three step backward to obtain the corresponding letter of the second group.

Each letter of the first group is moved eight steps forward to obtain the corresponding letter of the second group.

Each letter of the first group is moved one step forward to obtain the corresponding letter of the second group.

The 1st and 3rd letter of the group are each moved to 1 step backward while the 2nd and 4th letters are each moved one step forward to the corresponding letters the second group.

This is an alternating repetition series. The number 32 alternates with a series in which each number decreases by 2.

Two patterns alternate here. The first pattern begins with 10 and adds 2 to each
number to arrive at the next; the alternating pattern begins with 34 and subtracts 3 each
time.