%I #14 Feb 12 2021 19:42:00

%S 1,1,2,8,63,893,19714,597510,22903403,1056115331,56744710974,

%T 3475626211316,238818544070905,18183183610029003,1519020289266947462,

%U 138117136134012654182,13576724206357958780409,1434561741418662640589225,162136032834834405685977058,19516966563322659948894106704

%N Number of outerplanar graphs on n labeled nodes.

%H Andrew Howroyd, <a href="/A098000/b098000.txt">Table of n, a(n) for n = 0..200</a>

%H M. Bodirsky and M. Kang, <a href="http://www.informatik.hu-berlin.de/~bodirsky/publications/asymptoticBK.html">The asymptotic number of outerplanar graphs</a>.

%H S. R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/">Planar graph growth constants</a>.

%H Steven R. Finch, <a href="/A097999/a097999.pdf">Planar graph growth constants</a> [Cached copy, with permission of the author]

%F Recurrence known, see Bodirsky and Kang.

%F Exponential transform of A097998. - _Andrew Howroyd_, Feb 12 2021

%o (PARI) seq(n)={Vec(serlaplace(exp(intformal(serreverse(x/exp((1 + 5*x - sqrt(1 - 6*x + x^2 + O(x^n)))/8))/x))))} \\ _Andrew Howroyd_, Feb 12 2021

%Y Cf. A097998, A097999, A111564, A005470.

%K nonn

%O 0,3

%A _Steven Finch_, Sep 08 2004

%E a(0)=1 prepended and terms a(17) and beyond from _Andrew Howroyd_, Feb 12 2021