OFFSET
0,3
COMMENTS
The rank of a poset is the number of cover relations in a maximal chain.
A cover relation in a poset is an ordered pair x <= y such that there is no z with x <= z <= y.
LINKS
Eric Weisstein's World of Mathematics, Cover Relation.
FORMULA
a(n) = Sum_{k=1..floor(n^2/4)} A052296(n,k)*k.
MATHEMATICA
nn = 16; Table[Table[n!, {n, 0, nn}] CoefficientList[D[Series[Sum[Exp[y x]^Binomial[n, i]*Exp[ x]^(2^n - Binomial[n, i] - 1) x^n/n!, {n, 0, nn}], {x, 0, nn}], y] /. y -> 1, x]*i, {i, 1, nn - 1}] // Total
CROSSREFS
KEYWORD
nonn
AUTHOR
Geoffrey Critzer, Feb 05 2024
STATUS
approved