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A046912
Number of irreducible quasiorders with n labeled points.
2
1, 1, 2, 11, 147, 3412, 121553, 6353629, 476850636, 50811255045, 7636459252135, 1610584897516674, 474333338553730879, 194055026319667963777, 109692570582311591696890, 85221064877720762475072503, 90542406571528792666541430863, 130936936785995060562730057163556, 256634185641525450158992588551158389
OFFSET
0,3
LINKS
FORMULA
E.g.f.: A(x) = 2-1/B(x), where B(x) is e.g.f. of A000798. - Vladeta Jovovic, Jan 10 2006
MATHEMATICA
A000798 = Cases[Import["https://oeis.org/A000798/b000798.txt", "Table"], {_, _}][[All, 2]]; lg = Length[A000798];
B[x_] = Sum[A000798[[n + 1]] x^n/n!, {n, 0, lg - 1}];
A[x_] = 2 - 1/B[x];
CoefficientList[A[x] + O[x]^lg, x]*Range[0, lg - 1]! (* Jean-François Alcover, Jan 01 2020 *)
CROSSREFS
Cf. A046911.
Sequence in context: A348797 A204243 A203203 * A185245 A006122 A111014
KEYWORD
nonn,more
AUTHOR
John A. Wright.
EXTENSIONS
Corrected and extended by Vladeta Jovovic, Jan 10 2006
a(16)-a(18) from A000798 by Jean-François Alcover, Jan 01 2020
STATUS
approved