OFFSET
0,1
LINKS
M. Golriz, M. R. Darafsheh, and M. H. Khalifeh, The Wiener, Szeged and PI-indices of a phenylazomethine dendrimer, Digest J. Nanomaterials and Biostructures, 6, No. 4, 2011, 1545-1549.
FORMULA
a(n) = 27060 + 2^n*(-4550*n^2 +16990*n -243062) + 4^n*(67600*n^2-133640*n+219724).
G.f.: 2*(1861+54917*x-94376*x^2-382948*x^3+635520*x^4+150336*x^5)/((1-x)*(1-2*x)^3*(1-4*x)^3). - Bruno Berselli, Dec 30 2012
MAPLE
a := proc (n) options operator, arrow: 27060+2^n*(-4550*n^2+16990*n-243062)+4^n*(67600*n^2-133640*n+219724) end proc: seq(a(n), n = 0 .. 18);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Dec 29 2012
STATUS
approved