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%I #13 Nov 23 2024 00:29:09
%S 1,3,13,65,354,2035,12151,74618,468233,2989093,19350384,126730636,
%T 838161358,5589998777,37552863737,253877488505,1725951649616,
%U 11791929640102,80921655496164,557538161292336,3855215134210479,26745074320086283,186095529221819237,1298423607303399905
%N Number of connected matchings with n crossings, in a disk.
%H Andrew Howroyd, <a href="/A232222/b232222.txt">Table of n, a(n) for n = 1..200</a>
%H V. Pilaud, J. Rué, <a href="http://arxiv.org/abs/1307.6440">Analytic combinatorics of chord and hyperchord diagrams with k crossings</a>, arXiv preprint arXiv:1307.6440, 2013.
%o (PARI) {my(A=T(20)); vector(#A, i, vecsum(A[i]))} \\ T(n) defined in A232223. - _Andrew Howroyd_, Nov 22 2024
%Y Row sums of A232223.
%Y Cf. A000699.
%K nonn
%O 1,2
%A _N. J. A. Sloane_, Nov 22 2013
%E a(11) onwards from _Andrew Howroyd_, Nov 22 2024