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 A000251 Number of trees of diameter 6. (Formerly M2887 N1158) 2
 1, 3, 11, 29, 74, 167, 367, 755, 1515, 2931, 5551, 10263, 18677, 33409, 59024, 102984, 177915, 304458, 516939, 871180, 1458882, 2428548, 4021670, 6627515, 10874462, 17770474, 28932739, 46943967, 75925797, 122433291, 196879385, 315759282, 505168033, 806290796, 1284034606, 2040485004, 3235965074, 5121801962, 8091411114, 12759606939, 20085832527, 31565046053, 49523414558, 77575278933, 121329065354, 189475663960, 295465391518, 460087656595, 715436020515, 1110994054004 (list; graph; refs; listen; history; text; internal format)
 OFFSET 7,2 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS J. Riordan, Enumeration of trees by height and diameter, IBM J. Res. Dev. 4 (1960), 473-478. CROSSREFS Cf. A034853, A000550 (diameter 7). Sequence in context: A188475 A072610 A110954 * A159229 A239713 A122023 Adjacent sequences:  A000248 A000249 A000250 * A000252 A000253 A000254 KEYWORD nonn AUTHOR EXTENSIONS More terms from Sean A. Irvine, Nov 21 2010 STATUS approved

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