How many ways are there to put 5 balls in 3 boxes if the balls are not distinguishable but the boxes are?
+237 https://math.stackexchange.com/questions/340890/how-many-ways-are-there-to-distribute-5-balls-into-3-boxes-under-additional-con/340957#:~:text=Thus%20the%20total%20number%20of,balls%20in%203%20distinguishable%20boxes.
