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

Author

Peter Luschny, Aug 14 2019

Keywords

• nonn
• easy

Comments

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

Crossrefs

Cf. A260876, A260878, A326998.