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%I A093732 #19 Oct 06 2017 12:09:17
%S A093732 1,211,14221,636331,23679901,805351531,26175881341,831358677451,
%T A093732 26094426008221,814105545191851,25320182311228861,786251347986776971,
%U A093732 24394981288950302941,756583120577782494571,23459491617092461686781,727330825918603925122891
%N A093732 Number of connected relations.
%H A093732 T. D. Noe, <a href="/A093732/b093732.txt">Table of n, a(n) for n = 1..200</a>
%H A093732 G. Kilibarda and V. Jovovic, <a href="https://arxiv.org/abs/1411.4187">Enumeration of some classes of T_0-hypergraphs</a>, arXiv:1411.4187 [math.CO], 2014.
%H A093732 G. Kreweras, <a href="http://gallica.bnf.fr/ark:/12148/bpt6k480296q/f583.image">Inversion des polynômes de Bell bidimensionnels et application au dénombrement des relations binaires connexes</a>, C. R. Acad. Sci. Paris Ser. A-B 268 1969 A577-A579.
%H A093732 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (84,-2774,47548,-462525,2575088,-7643820,9374400).
%F A093732 a(n) = 31^n - 5*16^n - 10*10^n + 20*9^n + 30*7^n - 60*6^n + 24*5^n.
%F A093732 G.f.: -x*(1+127*x-729*x^2-20467*x^3+107048*x^4+259620*x^5) / ( (9*x-1)*(6*x-1)*(7*x-1)*(5*x-1)*(31*x-1)*(10*x-1)*(16*x-1) ). - _R. J. Mathar_, Jun 09 2013
%t A093732 Table[31^n - 5*16^n - 10*10^n + 20*9^n + 30*7^n - 60*6^n + 24*5^n, {n, 25}] (* _T. D. Noe_, May 29 2012 *)
%o A093732 (PARI) a(n)=31^n-5*16^n-10*10^n+20*9^n+30*7^n-60*6^n+24*5^n \\ _Charles R Greathouse IV_, Jun 16 2015
%Y A093732 Cf. A005333, A001047, A002501, A002502, A093733.
%K A093732 nonn,easy
%O A093732 1,2
%A A093732 Goran Kilibarda, _Vladeta Jovovic_, Apr 14 2004

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