|
|
A218106
|
|
Number of transitive reflexive early confluent binary relations R on n+6 labeled elements with max_{x}(|{y : xRy}|) = n.
|
|
2
|
|
|
0, 1, 80963, 25188019, 1913052805, 84934607175, 3085918099231, 104970367609107, 3527548086703069, 119752042470064290, 4150321205365373610, 147666165472551221730, 5409628424337030402002, 204363410596110256258446, 7966805463258438079563650
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
COMMENTS
|
R is early confluent iff (xRy and xRz) implies (yRz or zRy) for all x, y, z.
|
|
LINKS
|
|
|
FORMULA
|
|
|
MAPLE
|
t:= proc(k) option remember; `if` (k<0, 0, unapply (exp (add (x^m/m! *t(k-m)(x), m=1..k)), x)) end: tt:= proc(k) option remember; unapply ((t(k)-t(k-1))(x), x) end: T:= proc(n, k) option remember; coeff (series (tt(k)(x), x, n+1), x, n) *n! end:
a:= n-> T(n+6, n): seq (a(n), n=0..20);
|
|
MATHEMATICA
|
m = 6; f[0, _] = 1; f[k_, x_] := f[k, x] = Exp[Sum[x^m/m!*f[k-m, x], {m, 1, k}]]; (* t = A135302 *) t[0, 0] = 1; t[_, 0] = 0; t[n_, k_] := t[n, k] = SeriesCoefficient[f[k, x], {x, 0, n}]*n!; a[0] = 0; a[n_] := t[n+m, n]-t[n+m, n-1]; Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Feb 14 2014 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|