OFFSET
0,1
COMMENTS
a(0) has been checked by the direct computation of the Wiener index (using Maple).
LINKS
H. Yousefi-Azari, A. R. Ashrafi, and M. H. Khalifeh, Wiener index of micelle-like chiral dendrimers, Studia UBB, Chemia, 55, No. 4, 125-130, 2010.
Index entries for linear recurrences with constant coefficients, signature (13,-64,148,-160,64).
FORMULA
a(n) = 1189 + 15616*2^n + 7680*4^n + 12288*n*4^n + 4224*n*2^n (agrees with Theorem 2 of the Yousefi-Azari et al. reference).
G.f.: (24485-197564*x+610948*x^2-794080*x^3+366912*x^4)/((1-x)*(1-2*x)^2*(1-4*x)^2). [Bruno Berselli, Apr 06 2013]
MAPLE
a := proc (n) options operator, arrow: 1189 + 15616*2^n + 4224*2^n*n + 12288*4^n*n + 7680*4^n end proc: seq(a(n), n = 0 .. 18);
MATHEMATICA
CoefficientList[Series[(24485 - 197564 x + 610948 x^2 - 794080 x^3 + 366912 x^4)/((1 - x) (1 - 2 x)^2 (1 - 4 x)^2), {x, 0, 20}], x] (* Bruno Berselli, Apr 06 2013 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Apr 06 2013
STATUS
approved