1838: 7384

Nice little puzzle. With only one input-output pair (1838 -> 7384), there are many possible rules. If you want a concrete rule that fits this pair and also tells you the next term (if the pattern continues), here’s one simple, self-consistent option: Rule (digit-wise, four digits long): - Let the digits be a b c d (so 1838 has a=1, b=8, c=3, d=8). - Transform to a' b' c' d' by: - a' = a + 6 - b' = b - 5 - c' = c + 5 - d' = d - 4 Applying to 1838: - a' = 1 + 6 = 7 - b' = 8 - 5 = 3 - c' = 3 + 5 = 8 - d' = 8 - 4 = 4 Result: 7384 If you’d like, I can test other plausible rules or try to predict the next term if you have another pair (or a hint about the source of the puzzle). Do you have more examples or a hint about the expected pattern?