[AnnikaL]

> so that if another person is shown your sequence of digits from 1 to 6, he/she should not be able to tell whether these numbers were produced by a real die or just "made up" by somebody

This explanation leads me to think that the decision of what is random in the study is based on human perceptions of randomness, not actual statistical randomness. Although any sequence is equally (un)likely to be rolled, 1111111111 would stand out from the other sequences much more than 3156263441.