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 A122085 Triangle read by rows: T(n,k) = number of unlabeled free bicolored trees with n nodes (n >= 1) and k (1 <= k <= n-1, except k=0 or 1 if n=1, k=1 if n=2) nodes of one color and n-k nodes of the other color (the colors are not interchangeable). 2
 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 4, 2, 1, 1, 3, 7, 7, 3, 1, 1, 3, 10, 14, 10, 3, 1, 1, 4, 14, 28, 28, 14, 4, 1, 1, 4, 19, 45, 65, 45, 19, 4, 1, 1, 5, 24, 73, 132, 132, 73, 24, 5, 1, 1, 5, 30, 105, 242, 316, 242, 105, 30, 5, 1, 1, 6, 37, 152, 412, 693, 693, 412, 152 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,10 REFERENCES R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1978. LINKS R. W. Robinson, Rows 1 through 30, flattened EXAMPLE K M N gives the number N of unlabeled free bicolored trees with K nodes of one color and M nodes of the other color. 0 1 1 1 0 1 Total( 1) = 2 1 1 1 Total( 2) = 1 1 2 1 2 1 1 Total( 3) = 2 1 3 1 2 2 1 3 1 1 Total( 4) = 3 1 4 1 2 3 2 3 2 2 4 1 1 Total( 5) = 6 1 5 1 2 4 2 3 3 4 4 2 2 5 1 1 Total( 6) = 10 CROSSREFS Row sums give A122086. Sequence in context: A034851 A172453 A172479 * A209612 A209805 A238453 Adjacent sequences:  A122082 A122083 A122084 * A122086 A122087 A122088 KEYWORD nonn,tabf AUTHOR N. J. A. Sloane, Oct 19 2006 STATUS approved

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Last modified March 17 18:39 EDT 2018. Contains 300573 sequences. (Running on oeis4.)