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 A296526 Number of connected k-regular graphs on 2*n nodes with maximal diameter D(n,k) A296525 written as array T(n,k), 2 <= k < 2*n. 4
 1, 1, 1, 2, 1, 1, 1, 3, 6, 3, 1, 1, 1, 1, 35, 60, 21, 5, 1, 1, 1, 2, 16, 2391, 7849, 1547, 94, 9, 1, 1, 1, 1, 58, 1, 2757433, 21609301, 3459386, 88193, 540, 13, 1, 1, 1, 4, 1, 154 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,4 REFERENCES See A296525 for references and links. LINKS EXAMPLE Degree r         2   3   4   5    6        7        8     9   10   11 12 13 14 15    n  ------------------------------------------------------------------    4 |  2   1  Diameter A296525      |  1   1  Number of graphs with this diameter (this sequence)      |    6 |  3   2   2   1      |  1   2   1   1      |    8 |  4   3   2   2    2        1      |  1   3   6   3    1        1      |   10 |  5   5   3   2    2        2       2      1      |  1   1  35  60   21        5       1      1      |   12 |  6   6   4   3    2        2       2      2    2    1      |  1   2  16 2391 7849     1547     94      9    1    1      |   14 |  7   8   5   5    3        2       2      2    2    2  2  1      |  1   1  58   1 2757433 21609301 3459386 88193 540  13  1  1      |                 lower bounds   16 |  8   9   7   5  >=4      >=3       2      2    2    2  2  2  2  1      |  1   4   1  154   ?        ?       ?      ?    ?    ?4207 21 1  1      |              lower bounds   18 |  9  11 >=8 >=6  >=4      >=4     >=3      2    2    2  2  2  2  2      |  1   1   ?   ?    ?        ?       ?      ?    ?    ?  ? ?42110 33 . a(35)=1 corresponds to the only 5-regular graph on 14 nodes with diameter 5. Its adjacency matrix is .       1 2 3 4 5 6 7 8 9 0 1 2 3 4    1  . 1 1 1 1 1 . . . . . . . .    2  1 . 1 1 1 1 . . . . . . . .    3  1 1 . 1 1 . 1 . . . . . . .    4  1 1 1 . . 1 1 . . . . . . .    5  1 1 1 . . 1 1 . . . . . . .    6  1 1 . 1 1 . 1 . . . . . . .    7  . . 1 1 1 1 . 1 . . . . . .    8  . . . . . . 1 . 1 1 1 1 . .    9  . . . . . . . 1 . 1 1 . 1 1   10  . . . . . . . 1 1 . . 1 1 1   11  . . . . . . . 1 1 . . 1 1 1   12  . . . . . . . 1 . 1 1 . 1 1   13  . . . . . . . . 1 1 1 1 . 1   14  . . . . . . . . 1 1 1 1 1 . . A shortest walk along 5 edges is required to reach node 13 from node 1. All others of the A068934(97)=3459383 5-regular graphs on 14 nodes have smaller diameters, i.e., 258474 with diameter 2, 3200871 with diameter 3, and 37 with diameter 4 (see A296621). CROSSREFS Cf. A068934, A204329, A294733, A296524, A296525, A296621. Sequence in context: A291709 A326323 A257493 * A259844 A112707 A196017 Adjacent sequences:  A296523 A296524 A296525 * A296527 A296528 A296529 KEYWORD nonn,tabf,hard,more AUTHOR Hugo Pfoertner, Dec 14 2017 STATUS approved

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Last modified January 23 19:12 EST 2020. Contains 331175 sequences. (Running on oeis4.)