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%I #25 Jan 22 2017 21:24:16
%S 1,2,8,16,128,1280,3072,215040,3440640,2293760,137625600,201850880,
%T 72666316800,1889324236800,52901078630400,176336928768000,
%U 135426761293824,191854578499584000,1593868805996544000,787371190162292736000,31494847606491709440000,29395191099392262144000
%N Denominators of coefficients in asymptotic expansion of C_n (number of connected chord diagrams, A000699).
%H Gheorghe Coserea, <a href="/A280777/b280777.txt">Table of n, a(n) for n = 0..101</a>
%H Michael Borinsky, <a href="https://arxiv.org/abs/1603.01236">Generating asymptotics for factorially divergent sequences</a>, arXiv preprint arXiv:1603.01236 [math.CO], 2016.
%e Coefficients are 1, -5/2, -43/8, -579/16, -44477/128, -5326191/1280, -180306541/3072, ...
%o (PARI)
%o A000699_seq(N) = {
%o my(a = vector(N)); a[1] = 1;
%o for (n=2, N, a[n] = sum(k=1, n-1, (2*k-1)*a[k]*a[n-k])); a;
%o };
%o seq(N) = my(C = 'x*Ser(A000699_seq(N))); Vec(x*exp(1-(2*C+C^2)/(2*x))/C);
%o apply(denominator, seq(22)) \\ _Gheorghe Coserea_, Jan 22 2017
%Y Cf. A000699, A280775, A111111, A280776, A280778, A280779, A280780, A280781.
%K nonn,frac
%O 0,2
%A _N. J. A. Sloane_, Jan 19 2017
%E More terms from _Gheorghe Coserea_, Jan 22 2017
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