A360879 Number of unlabeled nonseparable (or 2-connected) loopless multigraphs with circuit rank n and degree >= 3 at each node.

0, 1, 4, 17, 118, 1198, 17133, 311757, 6803203

Offset

1,3

Links

Table of n, a(n) for n=1..9.

Martin Dowd, Some results on reconstructibility of colored graphs, IJPAM, 95 (2014), 309-321. Gives the sequence up to a(8) in Figure 1.

Martin Dowd, The source code of an implementation of the algorithm from the paper and data files containing the output graphs, 2024.

Zhizheng Ye, Xuewen Huang, Chuanyu Wu, Xianglei Xue and Liang Sun, Synthesis of contracted graph for planar nonfractionated simple-jointed kinematic chain based on similarity information, Mechanism and Machine Theory, 181 (2023), 105227. Gives the sequence in Table 3 with an erroneous term a(8) = 311737.

Formula

a(n) = Sum_{k=2..2*n-2} A046752(n + k - 1, k).

Crossrefs

Diagonal sums of A046752.

Cf. A002935, A360864.

Sequence in context: A271612 A240323 A335945 * A206353 A260694 A032115

Adjacent sequences: A360876 A360877 A360878 * A360880 A360881 A360882

Keyword

nonn,more

Author

Andrew Howroyd, Feb 25 2023

Extensions

a(8) from the paper by Martin Dowd (2014) and a(9) from Martin Dowd (personal communication) added by Andrey Zabolotskiy, Feb 21 2024

Status

approved