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Number of unlabeled nonseparable (or 2-connected) multigraphs with n edges, loops allowed.
1

%I #5 Feb 25 2023 20:57:58

%S 1,2,5,9,19,44,111,328,1090,3988,15838,67295,301417,1412821,6882398,

%T 34682721,180170661,962288228,5273162329

%N Number of unlabeled nonseparable (or 2-connected) multigraphs with n edges, loops allowed.

%Y Row sums of A360880.

%Y Cf. A007717, A007719, A010357.

%K nonn,more

%O 1,2

%A _Andrew Howroyd_, Feb 25 2023