A very small tweak, but it would be helpful if the OTUs (eg. in a *.shared file) could be numbered in a way that’s more consistent with how a computer thinks. Sorting lists, converting from text strings to numerical values, etc would be facilitated if some leading zeros could be inserted as follows.
otu1 … otu753
otu001 … otu753
Of course the tricky part is that the number of necessary leading zeros depends on the number of OTUs formed…