Welcome, Amelie, I hope that you'll enjoy being here. ;-) Surely you'll.
I love these kinds of discussion - I get thrilled with everything that has something to do with numbering, Combinations, Statistics and mathematics models, especially in its application in the photos of the Imperial family. (Am thinking to make some math models regarding the IF, but we'll see...).
There are not many pictures of Tatiana and Aleksei, either.
Correct -- but comparing to Aleksei and Maria photos together, Tatiana and Aleksei's photos together are not so rare (Remember cruising along the Dnieper with GD Dmitry Pavlovich in 1916). There are only a FEW ones of Maria and Aleksei photos together. I don't remember seeing so much Tatiana and Anastasia either.
Well done on good observation, Amelie and Sarah, that 'middle-pair' relationship between Gds Maria and Tatiana triggers questions within us.
We can make some statistic as well.
There were five Imperial Children.
Olga, Tatiana, Maria, Anastasia and Aleksei.
We will observe the situations of two or more participants in taking the photos, {2,3,4}. (The whole OTMAA and each single of them are not interesting to us.)
1. We can take two subjects of five in 10 ways. (So called
Binomial coefficient).So, we have the next combinations :
1. OT
2. OM
3. OA
4. OAleksei
5. TM
6. TA
7. TAleksei
8. MA
9. MAleksei
10. AAleksei
2. Analogically, we can take three of five subjects/objects in 10 ways again. Here they are:
1. OTM
2. OTA
3. OTAleksei
4. OMA
5. OMAleksei
6. OAAleksei
7. TMA
8. TMAleksei
9. TAAleksei
10. MAAleksei
And finally, we have 5 ways to take four of five subjects/objects.
1. OTMA, of course.
2. OTMAleksei
3. OTAAleksei
4. OMAAleksei
5. TMAAleksei.
How to do statistics? Collect ALL your OTMAA photos and just - count and put them in these 25 categories. It is bit hard due to two reasons -- we will never have ALL OTMAA photos and the second one -- it takes a lot of time.
The two-pairs are most interesting to us, of course. In the end, we could make percentage, and see many other things, for example, whom Tatiana enjoyed taking the photos most with?
Probably with Olga. Normally, she was older and there is bigger probability of existing more Olga and Tatiana than Tatiana and Anastasia (who was born 4 years after Tatiana) photos. Or we can see with whom Maria and Olga preferred taking photos with?