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A221010
The Wiener index of the nanostar dendrimer G[n], defined pictorially in the Nadjafi-Arani et al. reference.
1
84, 2328, 23070, 161322, 951906, 5097426, 25678002, 124125810, 582682098, 2676493554, 12091136754, 53909403378, 237825453810, 1040070008562, 4515386474226, 19482038992626, 83610263027442, 357169749688050, 1519594327768818, 6442039704551154
OFFSET
1,1
COMMENTS
a(2) has been checked by the direct computation of the Wiener index (using Maple).
The formula on p. 163 of the Nadjafi-Arani reference seems to be mistaken.
LINKS
M. J. Nadjafi-Arani, H. Khodashenas, and A. R. Ashrafi, A new method for computing Wiener index of dendrimer nanostars, MATCH Commun. Math. Comput. Chem. 69, 2013, 159-164.
FORMULA
a(n) = -270 + 2^(n-1)*2055+4^(n-1)*(1323*n-3024).
G.f.: -6*x*(-14-234*x-165*x^2+8*x^3) / ( (2*x-1)*(x-1)*(-1+4*x)^2 ). - R. J. Mathar, Apr 11 2013
MAPLE
a := proc (n) options operator, arrow: -270+2055*2^(n-1)+4^(n-1)*(1323*n-3024) end proc: seq(a(n), n = 1 .. 20);
CROSSREFS
Cf. A221011.
Sequence in context: A370572 A297486 A104674 * A219584 A140903 A219470
KEYWORD
nonn
AUTHOR
Emeric Deutsch, Mar 28 2013
STATUS
approved