What is the next term in the following sequence? N , O , M , P , L , Q , K , R…

In a composite alphabet series, two independent sub-series are interleaved together — the terms at odd positions follow one step-pattern and the terms at even positions follow a separate step-pattern. To find the missing terms, split the series into these two sub-series and extend each one independently using its own step size.

1. Split the sequence by position: the 1st, 3rd, 5th and 7th terms (the odd positions) are N, M, L, K; the 2nd, 4th, 6th and 8th terms (the even positions) are O, P, Q, R.

2. Convert each odd-position letter to its place in the alphabet: N = 14, M = 13, L = 12, K = 11 — each term is exactly one letter earlier than the one before it, so the odd-position run steps backward by one letter at a time.

3. Convert each even-position letter to its place in the alphabet: O = 15, P = 16, Q = 17, R = 18 — each term is exactly one letter later than the one before it, so the even-position run steps forward by one letter at a time.

4. The three missing terms occupy positions 9, 10 and 11 — position 9 continues the odd-position run one step beyond K, position 10 continues the even-position run one step beyond R, and position 11 continues the odd-position run one more step beyond that.

5. Extending each run by its established step size: the odd-position run continues K, J, I and the even-position run continues R, S — so positions 9, 10 and 11 are J, S and I.

Cross-check: writing out the full eleven-term sequence with alphabet values — N(14) O(15) M(13) P(16) L(12) Q(17) K(11) R(18) J(10) S(19) I(9) — the odd-position values fall steadily by one (14, 13, 12, 11, 10, 9) and the even-position values rise steadily by one (15, 16, 17, 18, 19) across every step, confirming the extension is consistent throughout, not just at the join.

So the next three terms are J, S, I.