Inconsistent SMALL Formula Results

Thank you for that assist. I guess you're saying that, if I have 50 columns containing 2020 (which, in some cases, I do), the values returned by SMALL (k=1 to 50) will all be 2020.

That seems to suggest, that if I were using something newer than Excel 2016, I would benefit from the UNIQUE function. I've looked for formulas or code providing a workaround, but what I've seen so far seems oriented toward producing vertical rather than horizontal lists, thus not filling Year columns to the right.

My data includes more than two years in some cases, and the years are not necessarily contiguous. Example: one row might have a number of entries in each of 2003, 2020, and 2021. I think there are not more than five years in any single row. Not sure yet; I'll have to see what I get in the five Years columns (i.e., 1-5) that I have set up at present.

To accommodate those additional columns, I tried modifying John's formula thus:

=IF(MAX(Year columns to the left)=(John's formula), produce a blank, otherwise produce John's formula)

But it seems John's formula is limited in any case to just one column (i.e., Year 2). Columns 3 through 5 are blank on all rows. I'm new to IFERROR and apparently don't quite understand it yet.

Bingo! That works. I've prepended an IF statement to eliminate some odd duplication, like this:

=IF(DTC4="","",IFERROR(SMALL($C4:$DSY4,COUNTIF($C4:$DSY4,"<="&DTC4)+1),""))

and that seems to do it. Testing continues, but so far it looks great.

Thank you again for your help. The larger project that this feeds into is still in progress, but in case anyone is interested, I've got an intermediate post that provides some context.

Keep up the good work!