A221013 The hyper-Wiener index of the nanostar dendrimer G_n , defined pictorially in the Golriz - Darafsheh - Khalifeh reference.

3722, 180552, 2683436, 25503780, 192352212, 1262648052, 7564190516, 42499015860, 227766985652, 1177463868852, 5916913295796, 29062281058740, 140094358522292, 664827881302452, 3113397432740276, 14415083971242420, 66086948110494132, 300376858346940852, 1354914339889899956

Offset

0,1

Links

Table of n, a(n) for n=0..18.

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

Cf. A221012.

Sequence in context: A237736 A289512 A260860 * A224436 A031559 A031739

Adjacent sequences: A221010 A221011 A221012 * A221014 A221015 A221016

Keyword

nonn,easy

Author

Emeric Deutsch, Dec 29 2012

Status

approved