A309725 Number of set partitions of {1,2,...,3n} with sizes in {[n, n, n], [2n, n], [3n]}.

3, 5, 31, 365, 6271, 129130, 2877421, 66628441, 1578320767, 37983592076, 925196176906, 22754692780561, 564123212097901, 14079691134569845, 353428830512017081, 8915830309096530865, 225890912989184760703, 5744976464242932324976, 146603288011226858621356

Offset

0,1

Comments

Fourth column in A260876. Apart from a(0) the same as A326998.

Links

Table of n, a(n) for n=0..18.

Crossrefs

Cf. A260876, A260878, A326998.

Sequence in context: A136361 A287474 A184302 * A290888 A318554 A109173

Adjacent sequences: A309722 A309723 A309724 * A309726 A309727 A309728

Keyword

nonn,easy

Author

Peter Luschny, Aug 14 2019

Status

approved