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A227488
The Wiener index of the nanostar dendrimer NSC_5C_6[n], defined pictorially in the Ashrafi et al. and the Rostami et al. references.
1
2192, 75884, 811076, 5876276, 35361428, 191654996, 973156820, 4730314964, 22295250644, 102723642068, 465158748884, 2077879380692, 9180871101140, 40201652095700, 174720788384468, 754542896859860, 3240816616917716
OFFSET
1,1
COMMENTS
a(2) has been checked by the direct computation of the Wiener index (using Maple).
LINKS
A. R. Ashrafi and P. Nikzad, Szeged index of nanostar dendrimers, Digest J. of Nanomaterials and Biostructures, 4, No. 1, 2009, 155-157.
M. Rostami, M. Shabanian, and H. Moghanian, Some topological indices for theoretical study of two types of nanostar dendrimers, Digest J. of Nanomaterials and Biostructures, 7, No. 1, 2012, 247-252.
FORMULA
a(n) = -13612 + 2^n*(72*n + 45270) + 4^n*(12960*n - 31680).
G.f. = 4*z*(548 + 11847*z -8782*z^2 - 33888*z^3 - 352*z^4)/((1-z)*(1-2*z)^2*(1-4*z)^2).
MAPLE
a := proc (n) options operator, arrow: -13612+2^n*(72*n+45270)+4^n*(12960*n-31680) end proc: seq(a(n), n = 1 .. 20);
CROSSREFS
Sequence in context: A251316 A320718 A134158 * A225719 A352344 A342428
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Jul 16 2013
STATUS
approved