OFFSET
1,1
COMMENTS
a(2) has been checked by the direct computation of the Wiener index (using Maple).
LINKS
A. R. Ashrafi and P. Nikzad, Szeged index of nanostar dendrimers, Digest J. of Nanomaterials and Biostructures, 4, No. 1, 2009, 155-157.
M. Rostami, M. Shabanian, and H. Moghanian, Some topological indices for theoretical study of two types of nanostar dendrimers, Digest J. of Nanomaterials and Biostructures, 7, No. 1, 2012, 247-252.
Index entries for linear recurrences with constant coefficients, signature (13,-64,148,-160,64).
FORMULA
a(n) = -13612 + 2^n*(72*n + 45270) + 4^n*(12960*n - 31680).
G.f. = 4*z*(548 + 11847*z -8782*z^2 - 33888*z^3 - 352*z^4)/((1-z)*(1-2*z)^2*(1-4*z)^2).
MAPLE
a := proc (n) options operator, arrow: -13612+2^n*(72*n+45270)+4^n*(12960*n-31680) end proc: seq(a(n), n = 1 .. 20);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Jul 16 2013
STATUS
approved