OFFSET
0,1
COMMENTS
a(0) and a(1) have been checked by the direct computation of the Wiener index (using Maple).
LINKS
M. K. Khalifeh, H. Yousefi-Azari, and A. R. Ashrafi, The Szeged and Wiener numbers of water soluble polyaryl ether dendrimer nanostars, Digest J. Nanomaterials and Biostructures, 4, 2009, 63-66.
FORMULA
a(n) = -6011+2^n*(-111166-5960*n+7000*n^2)+4^n*(151432-35200*n+40000*n^2).
G.f.: (34255 -252180*z + 1033772*z^2 -2480544*z^3+3259584*z^4-2547712*z^5+790528*z^6)/((1-z)*(1-2*z)^3*(1-4*z)^3).
MAPLE
a := proc (n) options operator, arrow: -6011+2^n*(-111166-5960*n+7000*n^2)+4^n*(151432-35200*n+40000*n^2) end proc: seq(a(n), n = 0 .. 20);
CROSSREFS
KEYWORD
nonn
AUTHOR
Emeric Deutsch, Jul 13 2013
STATUS
approved