OFFSET
1,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..100
Thomas Wieder, The number of certain rankings and hierarchies formed from labeled or unlabeled elements and sets, Applied Mathematical Sciences, vol. 3, 2009, no. 55, 2707 - 2724. [Thomas Wieder, Nov 14 2009]
FORMULA
CROSSREFS
KEYWORD
nonn
AUTHOR
Thomas Wieder, Sep 21 2008
EXTENSIONS
More terms from Alois P. Heinz, Apr 21 2012
STATUS
approved