OFFSET
1,1
COMMENTS
a(1) has been checked by the direct computation of the Wiener index (using Maple).
REFERENCES
A. Madanshekaf, The Randic index of some dendrimer nanostars, J. Appl. Math. & Informatics, 29, 2011, 1075-1080.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..300
FORMULA
a(n) = 4^n*(254016*n^2-728028*n+1207116) + 2^n*(13104*n^2-50682*n-1250685)+48039.
G.f.: 3*x*(134643-183720*x-400012*x^2-612832*x^3+2889984*x^4 -2158592*x^5 +762880*x^6)/((1-x)*(1-2*x)^3*(1-4*x)^3).
MAPLE
a := proc (n) options operator, arrow: 4^n*(254016*n^2-728028*n+1207116) +2^n*(13104*n^2-50682*n-1250685)+48039 end proc: seq(a(n), n = 1 .. 20);
MATHEMATICA
CoefficientList[Series[3 (134643 - 183720 x - 400012 x^2 - 612832 x^3 + 2889984 x^4 - 2158592 x^5 + 762880 x^6) / ((1 - x) (1 - 2 x)^3 (1 - 4 x)^3), {x, 0, 30}], x] (* Vincenzo Librandi, Aug 05 2013 *)
PROG
(Magma) [4^n*(254016*n^2-728028*n+1207116)+2^n*(13104*n^2-50682*n-1250685)+48039: n in [1..20]]; // Vincenzo Librandi, Aug 04 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Aug 03 2013
EXTENSIONS
Typo in the g.f. corrected from Bruno Berselli, Aug 05 2013
STATUS
approved