A014265 Number of trees on n nodes with forbidden limbs.

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

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