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A224432 The hyper-Wiener index of the dendrimer D_2[n], defined pictorially in the A. R. Ashrafi et al. reference. 1
622, 28413, 426343, 4177227, 32549395, 220006179, 1351039555, 7748170371, 42234607363, 221419948035, 1125752748547, 5584044867075, 27143513179651, 129736439305731, 611327539426819, 2845765137102339, 13108587035424259, 59831264715339267 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

a(2) has been checked by the direct computation of the hyper-Wiener index (using Maple).

REFERENCES

A. R. Ashrafi and H. Shabani, Computing Padmakar-Ivan index of four classes of dendrimers, Bulgarian Chem. Comm., 44, N0. 2, 2012, 127-130.

LINKS

Table of n, a(n) for n=0..17.

FORMULA

a(n) = - 2557 - 76735*2^n - 9768*2^n*n - 44640*4^n*n + 79914*4^n + 14400*4^n*n^2 + 2640*2^n*n^2.

G.f.=(622+16595z-20204z^2-56932z^3+33184z^4-51520z^5+9216z^6)/[(1-z)(1-2z)^3(1-4z)^3].

MAPLE

a := proc (n) options operator, arrow: -2557-76735*2^n-9768*2^n*n-44640*4^n*n+79914*4^n+14400*4^n*n^2+2640*2^n*n^2 end proc: seq(a(n), n = 0 .. 17);

CROSSREFS

Cf. A224431

Sequence in context: A251243 A184226 A260764 * A229318 A268025 A207554

Adjacent sequences:  A224429 A224430 A224431 * A224433 A224434 A224435

KEYWORD

nonn

AUTHOR

Emeric Deutsch, Apr 06 2013

STATUS

approved

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Last modified December 7 20:18 EST 2019. Contains 329847 sequences. (Running on oeis4.)