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 A084269 Triangle read by rows: T(n,k) is the number of simple connected graphs on n unlabeled nodes having chromatic number k, 1 <= k <= n. 8
 1, 0, 1, 0, 1, 1, 0, 3, 2, 1, 0, 5, 12, 3, 1, 0, 17, 64, 26, 4, 1, 0, 44, 475, 282, 46, 5, 1, 0, 182, 5036, 5009, 809, 74, 6, 1, 0, 730, 80947, 149551, 27794, 1940, 110, 7, 1, 0, 4032, 2010328, 7694428, 1890221, 113272, 4125, 156, 8, 1, 0, 25598, 76115143, 667036310, 248580644, 14545025, 389583, 8040, 212, 9, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,8 LINKS Eric Weisstein's World of Mathematics, n-Chromatic Graph EXAMPLE Triangle begins:   1;   0,   1;   0,   1,     1;   0,   3,     2,      1;   0,   5,    12,      3,     1;   0,  17,    64,     26,     4,    1;   0,  44,   475,    282,    46,    5,   1;   0, 182,  5036,   5009,   809,   74,   6, 1;   0, 730, 80947, 149551, 27794, 1940, 110, 7, 1;   ... CROSSREFS Row sums are A001349. Columns k=3..7 are A126737, A126738, A126739, A126740, A241702. Partial row sums include A005142, A076322, A076323, A076324, A076325, A076326, A076327, A076328. Essentially the same table as A126736. Cf. A084268 (not necessarily connected), A115597. Sequence in context: A128317 A179753 A279318 * A051427 A194763 A194741 Adjacent sequences:  A084266 A084267 A084268 * A084270 A084271 A084272 KEYWORD nonn,tabl AUTHOR Eric W. Weisstein, May 24 2003 EXTENSIONS a(37)-a(66) from Andrew Howroyd, Dec 02 2018 STATUS approved

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Last modified May 14 19:53 EDT 2021. Contains 343903 sequences. (Running on oeis4.)