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%I #6 Apr 07 2013 02:43:00
%S 622,28413,426343,4177227,32549395,220006179,1351039555,7748170371,
%T 42234607363,221419948035,1125752748547,5584044867075,27143513179651,
%U 129736439305731,611327539426819,2845765137102339,13108587035424259,59831264715339267
%N The hyper-Wiener index of the dendrimer D_2[n], defined pictorially in the A. R. Ashrafi et al. reference.
%C a(2) has been checked by the direct computation of the hyper-Wiener index (using Maple).
%D A. R. Ashrafi and H. Shabani, Computing Padmakar-Ivan index of four classes of dendrimers, Bulgarian Chem. Comm., 44, N0. 2, 2012, 127-130.
%F 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.
%F G.f.=(622+16595z-20204z^2-56932z^3+33184z^4-51520z^5+9216z^6)/[(1-z)(1-2z)^3(1-4z)^3].
%p 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);
%Y Cf. A224431
%K nonn
%O 0,1
%A _Emeric Deutsch_, Apr 06 2013
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