Hmmm....
Is this the unsolvable problem?
Having tried the examples in the links, Bernie's doesn't handle duplicates,
Peo's will only work for the 2nd mode, RD's doesn't handle duplicates, Ron's
doesn't handle duplicates, my attempt also didn't handle duplicates.
Harlan's does handle the duplicates but it needs a trap, otherwise, after
the last unique value is returned the formula starts "randomly" repeating
until it's been copied to more rows than the indexed range. (at which point
it errors as it should)
Harlan's formula with a trap:
=IF(ROWS($1:1)<=SUMPRODUCT((rng<>"")/COUNTIF(rng,rng&"")),INDEX(rng,MATCH(LARGE(FREQUENCY(rng,rng)+(1-ROW(INDIRECT("1:"&(ROWS(rng)+1)))/(ROWS(rng)+1)),ROW(A1)),FREQUENCY(rng,rng)+(1-ROW(INDIRECT("1:"&(ROWS(rng)+1)))/(ROWS(rng)+1)),0)),"")
See the link regarding some strange behavior of
SUMPRODUCT((rng<>"")/COUNTIF(rng,rng&"")):
http://tinyurl.com/jaen9
Biff