A227699 The Wiener index of the nanostar dendrimer defined pictorially in the Ashrafi et al. reference.

34081, 133753, 606505, 2879881, 13759561, 65105353, 303499465, 1393200841, 6306020041, 28195082953, 124751348425, 547085017801, 2381092856521, 10296337572553, 44275297821385, 189465493250761, 807328896525001, 3427204095550153

Offset

0,1

Comments

a(1) has been checked by the direct computation of the Wiener index (using Maple).

Links

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

A. R. Ashrafi, A. Karbasioun, and M. V. Diudea, Computing Wiener and detour indices of a new type of nanostar dendrimers, MATCH Commun. Math. Comput. Chem. 65, 2011, 193-200.

Formula

a(n) = 8905 + 2^(n)*(10560*n + 21528) + 4^(n)*(11520*n + 3648). Replacing n with n+1, we obtain the expression given in Theorem 1 of the Ashrafi et al. reference.

G.f.: (34081 - 309300*x + 1048900*x^2 - 1488480*x^3 + 794944*x^4)/((1-x)*(1-2*x)^2*(1-4*x)^2).

Maple

a := proc (n) options operator, arrow: 8905+2^n*(10560*n+21528)+4^n*(11520*n+3648) end proc: seq(a(n), n = 0 .. 22);

Crossrefs

Cf. A227700.

Sequence in context: A212229 A204669 A344666 * A234820 A182292 A206214

Adjacent sequences: A227696 A227697 A227698 * A227700 A227701 A227702

Keyword

nonn

Author

Emeric Deutsch, Jul 21 2013

Status

approved