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 A259862 Triangle read by rows: T(n,k) = number of unlabeled graphs with n nodes and connectivity exactly k (n>=1, 0<=k<=n-1). 42
 1, 1, 1, 2, 1, 1, 5, 3, 2, 1, 13, 11, 7, 2, 1, 44, 56, 39, 13, 3, 1, 191, 385, 332, 111, 21, 3, 1, 1229, 3994, 4735, 2004, 345, 34, 4, 1, 13588, 67014, 113176, 66410, 13429, 992, 54, 4, 1, 288597, 1973029, 4629463, 3902344, 1109105, 99419, 3124, 81, 5, 1, 12297299, 105731474, 327695586, 388624106, 162318088, 21500415, 820956, 9813, 121, 5, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS These are vertex-connectivities. Spanning edge-connectivity is A263296. Non-spanning edge-connectivity is A327236. Cut-connectivity is A327127. - Gus Wiseman, Sep 03 2019 LINKS Table of n, a(n) for n=1..66. Brendan McKay, confusion over k-connected graphs, posting to Sequence Fans Mailing List, Jul 08 2015. Jens M. Schmidt, Combinatorial Data Gus Wiseman, The graphs counted by row n = 5 (isolated vertices not shown). EXAMPLE Triangle begins: 1; 1, 1; 2, 1, 1; 5, 3, 2, 1; 13, 11, 7, 2, 1; 44, 56, 39, 13, 3, 1; 191, 385, 332, 111, 21, 3, 1; 1229, 3994, 4735, 2004, 345, 34, 4, 1; 13588, 67014, 113176, 66410, 13429, 992, 54, 4, 1; 288597, 1973029, 4629463, 3902344, 1109105, 99419, 3124, 81, 5, 1; 12297299,105731474,327695586,388624106,162318088,21500415,820956,9813,121,5,1; ... CROSSREFS Columns k=0..10 (up to initial nonzero terms) are A000719, A052442, A052443, A052444, A052445, A324234, A324235, A324088, A324089, A324090, A324091. Row sums are A000088. Number of graphs with connectivity at least k for k=1..10 are A001349, A002218, A006290, A086216, A086217, A324240, A324092, A324093, A324094, A324095. The labeled version is A327334. Cf. A002494, A263296, A322389, A326786, A327127, A327236. Sequence in context: A125800 A264698 A263296 * A182930 A232187 A076241 Adjacent sequences: A259859 A259860 A259861 * A259863 A259864 A259865 KEYWORD nonn,tabl AUTHOR N. J. A. Sloane, Jul 08 2015 STATUS approved

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Last modified December 4 10:17 EST 2023. Contains 367560 sequences. (Running on oeis4.)