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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 (list; graph; refs; listen; history; text; internal format)
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), 153-165.

Index entries for sequences related to trees

FORMULA

G.f. x^5 + t(x)-(t(x)^2-t(x^2))/2, where t(x) = (x-2*x^5+x^9)/[Product_{p>=1} (1-x^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

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Last modified November 29 18:13 EST 2022. Contains 358431 sequences. (Running on oeis4.)