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%I #9 Feb 21 2022 20:31:56
%S 0,2,74,2228,100494,6014932,453143662,41921209920,4639656895118,
%T 603202689990836,90714189165482310,15583340701180474312,
%U 3025677781064563172326,658038493760685537784572,159065982382639942877853134,42449055613405195868802686816
%N Number of minimal edge covers in the n-cocktail party graph.
%H Andrew Howroyd, <a href="/A351589/b351589.txt">Table of n, a(n) for n = 1..100</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CocktailPartyGraph.html">Cocktail Party Graph</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/MinimalEdgeCover.html">Minimal Edge Cover</a>
%F a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * (2*k)! * [x^(2*k)] B(n-k,x), where B(k,x) = (2*exp(x) - 1)^k * exp(-x - x^2/2 + x*exp(x)). - _Andrew Howroyd_, Feb 21 2022
%o (PARI) a(n)={my(x=x+O(x^(2*n+1)), p=exp(-x - x^2/2 + x*exp(x)), q=2*exp(x) - 1); sum(k=0, n, (-1)^(n-k)*binomial(n,k)*(2*k)!*polcoef(q^(n-k)*p, 2*k))} \\ _Andrew Howroyd_, Feb 21 2022
%Y Cf. A053530, A297029, A297474, A351588.
%K nonn
%O 1,2
%A _Eric W. Weisstein_, Feb 14 2022
%E Terms a(5) and beyond from _Andrew Howroyd_, Feb 21 2022