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 A275420 Triangle read by rows: T(n,k) = number of regular graphs with n nodes and k connected components. 1
 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 3, 2, 1, 1, 5, 5, 4, 2, 1, 1, 4, 9, 6, 4, 2, 1, 1, 17, 14, 12, 7, 4, 2, 1, 1, 22, 30, 19, 13, 7, 4, 2, 1, 1, 167, 56, 42, 22, 14, 7, 4, 2, 1, 1, 539, 224, 74, 47, 23, 14, 7, 4, 2, 1, 1, 18979, 785, 271, 87, 50, 24, 14, 7, 4, 2, 1, 1, 389436, 19783 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,7 COMMENTS Multiset transformation of A005177. LINKS FORMULA T(n,1) = A005177(n). T(n,k) = Sum_{c_i*N_i=n,i=1..k} binomial(T(N_i,1)+c_i-1,c_i) for 1=1} (1-y*x^j)^(-A005177(j)). - Alois P. Heinz, Apr 13 2017 EXAMPLE 1       1   1       1   1   1       2   2   1   1       2   3   2   1   1       5   5   4   2   1   1       4   9   6   4   2   1   1      17  14  12   7   4   2   1   1      22  30  19  13   7   4   2   1   1     167  56  42  22  14   7   4   2   1   1     539 224  74  47  23  14   7   4   2   1   1   18979 785 271  87  50  24  14   7   4   2   1   1 CROSSREFS Cf. A005177 (1st column), A165647 (row sums). Sequence in context: A011847 A091325 A193596 * A143974 A301565 A237265 Adjacent sequences:  A275417 A275418 A275419 * A275421 A275422 A275423 KEYWORD nonn,tabl AUTHOR R. J. Mathar, Jul 27 2016 STATUS approved

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Last modified February 18 02:57 EST 2020. Contains 332006 sequences. (Running on oeis4.)