[seqfan] Re: Clarifying A112531

[Jonas Wallgren]

> Please help clarifying the definition of the triangular array
> http://oeis.org/A112531

"Triangle read by rows which counts ordered partitions having at least one part equal to one."
"The partitions begin 1 2 11 3 22 21 111 4 33 32 222 31 221 211 1111 ..."

Keep the partitions containing 1:

1 11 21 111 31 221 211 1111 ...

The number of (different looking) permutations of each partition is:

1 1 2 1 2 3 3 1 ... =A112531

"permutations since we have omitted those cases having no part equal to one"

     /Jonas Wallgren, Linköping University