A094730 - OEIS

%I #10 Oct 08 2017 18:50:09

%S 0,1,1,25,337,4321,46681,437305,3721537,29740561,228000361,1699890985,

%T 12435686737,89792976001,642488104441,4567920215065,32331017955937,

%U 228106608326641,1605738151030921,11285298643841545,79223419486529137

%N Number of connected ordered 3-element multiantichains on a labeled n-set.

%H G. C. Greubel, <a href="/A094730/b094730.txt">Table of n, a(n) for n = 0..1000</a>

%F E.g.f.: exp(7*x) - 6*exp(5*x) + 3*exp(4*x) + 17*exp(3*x) - 30*exp(2*x) + 21*exp(x) - 6.

%F Empirical g.f.: -x*(5040*x^5 - 2686*x^4 + 843*x^3 - 193*x^2 + 21*x - 1) / ((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(7*x-1)). - _Colin Barker_, Jul 07 2013

%t With[{nmax = 50}, CoefficientList[Series[Exp[7*x] - 6*Exp[5*x] + 3*Exp[4*x] + 17*Exp[3*x] - 30*Exp[2*x] + 21*Exp[x] - 6, {x, 0, nmax}], x] Range[0, nmax]!] (* _G. C. Greubel_, Oct 08 2017 *)

%o (PARI) x='x+O('x^50); concat([0], Vec(serlaplace(exp(7*x) - 6*exp(5*x) + 3*exp(4*x) + 17*exp(3*x) - 30*exp(2*x) + 21*exp(x) - 6))) \\ _G. C. Greubel_, Oct 08 2017

%Y Cf. A094033-A094037, A094729-A094738.

%K nonn

%O 0,4

%A Goran Kilibarda, _Vladeta Jovovic_, May 24 2004