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A086864 a(n) = (n-1)*(n-2)*(n-3)*(3*n-10)*3^(n-5)/4. 0
0, 0, 0, 1, 30, 360, 2970, 19845, 115668, 612360, 3018060, 14073345, 62788770, 270208224, 1128426390, 4594307445, 18302828040, 71553216240, 275154640632, 1042806816225, 3901324324230, 14427539010360, 52801538445810, 191427950399301, 688082033693340 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,5
REFERENCES
L. Ericson et al., Enumeration of tree properties..., Algorithms Review, 1 (1990), 119-124.
LINKS
FORMULA
G.f.: x^4*(15*x+1)/(1-3*x)^5 [From Maksym Voznyy (voznyy(AT)mail.ru), Jul 26 2009]
a(1)=0, a(2)=0, a(3)=0, a(4)=1, a(5)=30, a(n)=15*a(n-1)-90*a(n-2)+ 270*a(n-3)- 405*a(n-4)+243*a(n-5). - Harvey P. Dale, May 15 2015
a(n) = A036217(n-4)+15*A036217(n-5). - R. J. Mathar, Apr 14 2018
MATHEMATICA
Table[((n-1)(n-2)(n-3)(3n-10)3^(n-5))/4, {n, 30}] (* or *) LinearRecurrence[ {15, -90, 270, -405, 243}, {0, 0, 0, 1, 30}, 30] (* Harvey P. Dale, May 15 2015 *)
CROSSREFS
Sequence in context: A222086 A008656 A179717 * A138441 A058837 A042748
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Sep 16 2003
EXTENSIONS
G.f. proposed by Maksym Voznyy checked and corrected by R. J. Mathar, Sep 16 2009.
Definition clarified by Harvey P. Dale, May 15 2015
STATUS
approved

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Last modified April 15 12:18 EDT 2024. Contains 371686 sequences. (Running on oeis4.)