0,9

David Applegate and N. J. A. Sloane, The Gift Exchange Problem (arXiv:0907.0513, 2009)

Triangle begins:

1

0,1

0,1,1

0,1,3,1

0,1,7,6,1

0,0,15,25,10,1

0,0,25,90,65,15,1

0,0,35,280,350,140,21,1

0,0,35,770,1645,1050,266,28,1

0,0,0,1855,6930,6825,2646,462,36,1

0,0,0,3675,26425,39795,22575,5880,750,45,1

0,0,0,5775,90475,211750,172095,63525,11880,1155,55,1

0,0,0,5775,275275,1033725,1198120,609840,158235,22275,1705,66,1

0,0,0,0,725725,4629625,7702695,5335330,1861860,358215,39325,2431,78,1

0,0,0,0,1576575,18918900,45965920,43158115,19899880,5060055,750750,66066,3367,91,1

0,0,0,0,2627625,69719650,254879625,325475150,196471275,64689625,12522510,1476475,106470,4550,105,1

Sequence in context: A106800 A055807 A054024 this_sequence A151509 A151511 A048993

Adjacent sequences: A144641 A144642 A144643 this_sequence A144645 A144646 A144647

nonn,tabl

David Applegate and N. J. A. Sloane (njas(AT)research.att.com), Jan 25 2009