A318399
Number of triples of set partitions of {1,...,n} with meet {{1},...,{n}} and join {{1,...,n}}.
Original entry on oeis.org
1, 6, 84, 2226, 93246, 5616492, 459173406, 48933260388, 6595445513412, 1098326915060730, 221772386369110242, 53460963703982862534, 15185890964240671486740, 5026315912246843181692776, 1919721040169845172603949966, 838872819016448052585038291124
Offset: 1
The a(2) = 6 triples:
{{1},{2}} {{1},{2}} {{1,2}}
{{1},{2}} {{1,2}} {{1},{2}}
{{1},{2}} {{1,2}} {{1,2}}
{{1,2}} {{1},{2}} {{1},{2}}
{{1,2}} {{1},{2}} {{1,2}}
{{1,2}} {{1,2}} {{1},{2}}
Cf.
A000110,
A000258,
A001247,
A008277,
A048994,
A059849,
A060639,
A181939,
A318389,
A318390,
A318391,
A318392,
A318393,
A318398.
-
nn=20;
Table[n!*SeriesCoefficient[Log[1+Sum[x^k/k!*Sum[StirlingS1[k,i]*BellB[i]^3,{i,0,k}],{k,nn}]],{x,0,n}],{n,nn}]
A318815
Number of triples of set partitions of {1,2,...,n} whose join is {{1,2,...,n}}.
Original entry on oeis.org
1, 7, 103, 2773, 117697, 7167619, 590978941, 63385879261, 8584707943381, 1434654097736101, 290409845948305321, 70125579500764771585, 19940633217840575968969, 6603748351832744611210549, 2522614472277243822293033719, 1102166886808604068546379343289
Offset: 1
The a(2) = 7 triples:
{{1},{2}} {{1},{2}} {{1,2}}
{{1},{2}} {{1,2}} {{1},{2}}
{{1},{2}} {{1,2}} {{1,2}}
{{1,2}} {{1},{2}} {{1},{2}}
{{1,2}} {{1},{2}} {{1,2}}
{{1,2}} {{1,2}} {{1},{2}}
{{1,2}} {{1,2}} {{1,2}}
Cf.
A000110,
A000258,
A001247,
A008277,
A048994,
A059849,
A060639,
A181939,
A318389,
A318391,
A318393,
A318398,
A318399.
-
nn=10;Table[n!*SeriesCoefficient[Log[1+Sum[BellB[n]^3*x^n/n!,{n,nn}]],{x,0,n}],{n,nn}]
Showing 1-2 of 2 results.