

A014265


Number of trees on n nodes with forbidden limbs.


1



0, 1, 1, 1, 2, 2, 4, 7, 15, 30, 68, 146, 340, 786, 1878, 4507, 11045, 27220, 67956, 170766, 432818, 1103539, 2831814, 7303966, 18934866, 49302321, 128910528, 338329555, 891099316, 2354613762, 6240696052, 16587146598, 44203851675, 118093003229
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OFFSET

0,5


LINKS

Table of n, a(n) for n=0..33.
T. Lu, The enumeration of trees with and without given limbs, Discr. Math., 154 (1996), 153165.
Index entries for sequences related to trees


FORMULA

G.f. x^5 + t(x)(t(x)^2t(x^2))/2, where t(x) = (x2*x^5+x^9)/[Product_{p>=1} (1x^p)^b(p)] is the implicit form of the ordinary generating function of the sequence b(n>=0) = 0,1, 1, 2, 4, 7, 16, 38, 89, 217, 535, 1340, 3391, 8686, 22421, 58355, 152859,...  R. J. Mathar, Feb 27 2016


CROSSREFS

Sequence in context: A118988 A049904 A049906 * A153967 A052949 A014266
Adjacent sequences: A014262 A014263 A014264 * A014266 A014267 A014268


KEYWORD

nonn


AUTHOR

N. J. A. Sloane.


STATUS

approved



