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 1 15 25 10 1

0 1 31 90 65 15 1

0 0 63 301 350 140 21 1

0 0 119 966 1701 1050 266 28 1

Sequence in context: A054024 A144644 A151509 this_sequence A048993 A112413 A122960

Adjacent sequences: A151508 A151509 A151510 this_sequence A151512 A151513 A151514

nonn,tabl,easy,more

N. J. A. Sloane (njas(AT)research.att.com), May 14 2009