The graphic here shows three pages of a series of 4 flows (a set of etudes).
???
Does changing the options to hide the header above flow headings in the Flows section of the Page Setup page of Layout Options do the trick?
Actually, the First masterpage (used in all the pages where a new flow starts) does not have the {@page@} token, this is why no page numbers appear. The easiest way I think of is to edit the First masterpage so that the tokens are there (like for the default masterpage), and manually edit the first time the First masterpage appears to delete that token, if you do not want page 1 number to appear. Not easy to explain, but actually quite easy to make.
Marc, look at the screenshot carefully - the page in question uses the Default master page, not the First master page. I suspect Florian has given the correct answer 
Oh yes right! 
I changed the options as suggested. Still no change.
I finally found a workaround: I have another set of piano pieces where the page numbers work fine. So I imported all the “etudes” flows into that, and then deleted that piece’s old flows. But I still wish I could understand what the problem was!
belkina,
I am glad you found a solution. It looks to me that perhaps you made a change to the Default master page (perhaps deleting the page token?), and then copied it L to R, because of the location of the token. Here is what the Default master page looks without any tweaking (I’m using Petaluma Font here). You will notice the partial Page# token, as well as the location of the token in upper left for a left page and upper right and right justified for a right page.
I found another solution: I just created a new text frame for the page token at the top of the Master Page. I had been trying to modify what was already there. This seems to be the simplest solution.
Thank you all for your input. I’ve used Dorico for composing a lot, but I am only now getting to know Engrave Mode. 
