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 A221006 The Wiener index of the nanostar dendrimer NS[n], defined pictorially in the Karbasioun-Ashrafi-Diudea reference. 1
 1296, 14526, 107082, 649890, 3539538, 18027954, 87813234, 414505458, 1911928050, 8665131762, 38733797106, 171235454706, 750157258482, 3261519544050, 14089697722098, 60533384085234, 258832139157234, 1102123427954418, 4675674117242610, 19771419930918642, 83360577251966706 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Table of n, a(n) for n=0..20. A. Karbasioun, A. R. Ashrafi, and M. V. Diudea, Distance and detour matrices of an infinite class of dendrimer nanostars, MATCH Commun. Math. Comput. Chem. 63, 2010, 239-246. Index entries for linear recurrences with constant coefficients, signature (11,-42,64,-32). FORMULA a(n) = -270 + 2^n*3510+4^n*(3888*n-1944) (see Theorem 1 in the Karbasioun-Ashrafi-Diudea reference). G.f.: -54*(16*x^3-32*x^2-5*x-24) / ((x-1)*(2*x-1)*(4*x-1)^2). [Colin Barker, Jan 01 2013] MAPLE a := proc (n) options operator, arrow: -270+3510*2^n+4^n*(3888*n-1944) end proc: seq(a(n), n = 0 .. 20); CROSSREFS Cf. A221007. Sequence in context: A137488 A189991 A250438 * A016864 A064785 A223560 Adjacent sequences: A221003 A221004 A221005 * A221007 A221008 A221009 KEYWORD nonn,easy AUTHOR Emeric Deutsch, Dec 29 2012 STATUS approved

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Last modified June 20 18:51 EDT 2024. Contains 373532 sequences. (Running on oeis4.)