[seqfan] a sequence to check

[David Newman]

I'd like someone to check (and extend) the following.

What is the number of plane partitions each of whose summands is used a
different number of times.

As an example for n=3 there are 4 such partitions

3

111

11
1

and

1
1
1.

The plane partitions

21 and

2
1

do not appear on the list because each of the summands "2" and "1" is used
the same number of times.


The numbers that I've gotten, for n=1 until n=6, by hand calculations are:
1,3,4,11,20, and 31