The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A014273 Number of trees on n nodes with forbidden limbs. 2
 0, 1, 2, 5, 19, 73, 297, 1256, 5467, 24368, 110610, 509715, 2377978, 11210451, 53318599, 255537199, 1232866889, 5982965779, 29185293329, 143026402189, 703829126231, 3476496240860, 17230140895115, 85659915381510, 427065111704502, 2134705956413458 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Vaclav Kotesovec, Table of n, a(n) for n = 0..1000 T. Lu, The enumeration of trees with and without given limbs, Discr. Math., 154 (1996), 153-165, Example 4. FORMULA G.f. (x-2*x^3+x^4)/[Product_{p >= 1} (1-x^p)^(2*a(p))], in implicit form. - R. J. Mathar, Feb 26 2016 a(n) ~ c * d^n / n^(3/2), where d = 5.31351404806511900111976949727598017431010423107784202438023676025442... and c = 0.19638268380963259854038594083610578852611575... . - Vaclav Kotesovec, Feb 28 2016 MATHEMATICA nmax = 30; b = ConstantArray[0, nmax+1]; b[[1]] = 0; b[[2]] = 1; Do[b[[n+1]] = SeriesCoefficient[(x - 2*x^3 + x^4) / Product[(1 - x^p)^(2*b[[p+1]]), {p, 1, n-1}], {x, 0, n}], {n, 2, nmax}]; b (* Vaclav Kotesovec, Feb 28 2016 *) CROSSREFS Sequence in context: A148436 A148437 A106873 * A255541 A150026 A150027 Adjacent sequences:  A014270 A014271 A014272 * A014274 A014275 A014276 KEYWORD nonn AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 16 04:56 EDT 2021. Contains 345056 sequences. (Running on oeis4.)