A227489 The hyper-Wiener index of the nanostar dendrimer NSC_5C_6[n], defined pictorially in the Ashrafi et al. and the Rostami et al. references.

9801, 800545, 14262241, 148766529, 1187870657, 8103701057, 49907422785, 286259766337, 1558851796033, 8161139590209, 41432038278209, 205221516272705, 996243752510529, 4755963555931201, 22386081148494913, 104106406002746433

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..16.

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) = 189505 + 2^(n)*(360*n^(2) - 1148*n - 1285024) + 4^(n)*(129600*n^(2) -627120*n + 1095500).

G.f. = z*(9801 +614326*z +522036*z^2 - 8367736*z^3+6785696*z^4+5562240*z^5-9728*z^6)/((1-z)*(1-2*z)^3*(1-4*z)^3).

Maple

a := proc (n) options operator, arrow: 189505+2^n*(360*n^2-1148*n-1285024)+4^n*(129600*n^2-627120*n+1095500) end proc: seq(a(n), n = 1 .. 18);

Crossrefs

Cf. A227488.

Sequence in context: A069333 A222814 A156735 * A350918 A113937 A036353

Adjacent sequences: A227486 A227487 A227488 * A227490 A227491 A227492

Keyword

nonn

Author

Emeric Deutsch, Jul 16 2013

Status

approved