Are recurred and reoccured both words in good standing, and if so, do you see any difference between the two?

I've always used recur and that's the only version in most of the dictionaries. Reoccur doesn't seem to be counted as a 'real' word, although I've seem it used often enough. I found that there were 363K ghits for reoccur but 3.4M for recur.

I think this is similar to "conferring" and "conferencing", the latter of which is occasionally used to mean the former.

At first I thought it was like "regardless" and "irregardless" and "orient" and "orientate," but I don't know. The COED seems to distinguish them a bit. It says that "reoccur" is to "occur again or repeatedly," and similarly "recur" is defined as to "occur again." However, instead of "recur" meaning to occur "repeatedly," it says, "(of a thought, image, etc.) come back to one’s mind." Does anyone know of this difference between the two words?

If I read your quotes right, COED is saying that either recur or reoccur applies when something happens a second time, but only reoccur applies to something that happens repeatedly, over and over and over again.

I'd think they have it precisely wrong: that recur implies "over and over", and reoccur applies only to a second appearance or occurrence, not to a successive series.

I am not sure that I have used "reoccur" before; I tend to use "recur," so I am not familiar with the distinction. Here is the COED link to recur and to reoccur.

I look rather askance at 'reoccur': for me the natural term for this is 'recur', and I think I've changed it in editing other people's writing. However, 'recur', as the older or more established term, might have acquired connotations for some people that make it marginally less suitable for the simplest literal sense. 'Recur' might imply some regularity, for example, as when we say a decimal expansion recurs.

One of OED's definitions of 'recur' is "Of events, facts, states, etc.: To occur, happen, take place, appear, again. (Common in 19th c.)," and for that it adds, "The context usually indicates repeated re-occurrence."

Similarly, 'recurrent' is defined as "3. Occurring or coming again (esp. frequently or periodically); reappearing. "

So it seems that while reoccur has the sense of 'again', recur has somewhat the sense of 'over and over again'.