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A218093
Number of transitive reflexive early confluent binary relations R on n labeled elements with max_{x}(|{y : xRy}|) = 3.
2
13, 106, 1105, 12075, 141533, 1812216, 25188019, 378725365, 6135529675, 106586385708, 1976799958367, 38978490654831, 814024466784025, 17943457752971680, 416183933276776375, 10128962147830237953, 258021086313431979827, 6863916836407264864380
OFFSET
3,1
COMMENTS
R is early confluent iff (xRy and xRz) implies (yRz or zRy) for all x, y, z.
REFERENCES
A. P. Heinz (1990). Analyse der Grenzen und Möglichkeiten schneller Tableauoptimierung. PhD Thesis, Albert-Ludwigs-Universität Freiburg, Freiburg i. Br., Germany.
LINKS
FORMULA
E.g.f.: exp(x*exp(x*exp(x)+x^2/2)+x^2/2*exp(x)+x^3/6)-exp(x*exp(x)+x^2/2).
a(n) = A210911(n) - A135312(n).
MAPLE
egf:= exp(x*exp(x*exp(x)+x^2/2)+x^2/2*exp(x)+x^3/6)-exp(x*exp(x)+x^2/2):
a:= n-> n!* coeff(series(egf, x, n+1), x, n):
seq(a(n), n=3..30);
CROSSREFS
Column k=3 of A135313.
Sequence in context: A055902 A295249 A295648 * A132261 A142364 A164301
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 20 2012
STATUS
approved