OFFSET
0,1
COMMENTS
a(0) has been checked by the direct computation of the Wiener index (using Maple).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Z. Yarahmadi, Eccentric connectivity and augmented eccentric connectivity indices of N-branches phenylacetylenes nanostar dendrimers, Iranian J. Math. Chem., 1, No. 2, 2010, 105-110.
Z. Yarahmadi and G. H. Fath-Tabar, The Wiener, Szeged, PI, Vertex PI, the first and second Zagreb indices of N-branched phenylacetylenes dendrimers, MATCH: Commun. Math. Comput. Chem, 65 (2011) 201-208.
Index entries for linear recurrences with constant coefficients, signature (15,-86,232,-288,128)
FORMULA
a(n) = 116340 - 2180388*2^n + 2132604*4^n - 2299671*4^n*n/2 + 613089*4^n*n^2.
G.f.: 6*(11426+185109*x+295053*x^2+31342*x^3+600*x^4)/((1-x)*(1-2*x)*(1-4*x)^3).
MAPLE
a := proc (n) options operator, arrow: 116340-(2299671/2)*4^n*n-2180388*2^n+2132604*4^n+613089*4^n*n^2 end proc: seq(a(n), n = 0 .. 16);
MATHEMATICA
CoefficientList[Series[6 (11426 + 185109 x + 295053 x^2 + 31342 x^3 + 600 x^4) / ((1 - x) (1 - 2 x) (1 - 4 x)^3), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 26 2013 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Apr 06 2013
STATUS
approved