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%I #19 May 06 2023 23:07:59
%S 1,-2,4,-10,30,-104,392,-1568,6520,-27976,122944,-551680,2518912,
%T -11684000,54957216,-261897024,1263216192,-6164172608,30416619200,
%U -151750104800,765364073120,-3902783995520,20123276097920
%N Reversion of sequence of involutions (A000085).
%H Andrew Howroyd, <a href="/A050397/b050397.txt">Table of n, a(n) for n = 1..200</a>
%H N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
%H <a href="/index/Res#revert">Index entries for reversions of series</a>
%p # Using function CompInv from A357588.
%p CompInv(23, n -> simplify(hypergeom([-n/2, (1-n)/2], [], 2))); # _Peter Luschny_, Oct 05 2022
%o (PARI) seq(n)=Vec(serreverse(serlaplace(-1 + exp(x+x^2/2 + O(x*x^n))))) \\ _Andrew Howroyd_, May 06 2023
%Y Cf. A000085, A050398.
%K sign
%O 1,2
%A _Christian G. Bower_, Nov 15 1999