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A143367 The Szeged index of third type dendrimer nanostar which has grown n stages. 1
9412, 30652, 123148, 564844, 2726572, 13219372, 63206188, 296679724, 1368005932, 6210491692, 27825661228, 123303445804, 541361800492, 2358354445612, 10205728212268, 43913619703084, 188020440958252, 801552290809132, 3404105445803308, 14408036898571564 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
A. Iranmanesh and N. Gholami, Computing the Szeged index of third and fourth dendrimer nanostars, Micro & Nano Letters, 2 (2007), 107-110.
FORMULA
a(n) = 3636*2^n + 1324 + 720*n*4^n + 1560*n*2^n - 1296*4^n.
G.f.: -4*x*(58624*x^4-116832*x^3+81760*x^2-22926*x+2353) / ((x-1)*(2*x-1)^2*(4*x-1)^2). - Colin Barker, Sep 20 2013
MAPLE
a:=3636*2^n+1324+720*n*4^n+1560*n*2^n-1296*4^n: seq(a(n), n=1..18);
MATHEMATICA
LinearRecurrence[{13, -64, 148, -160, 64}, {9412, 30652, 123148, 564844, 2726572}, 30] (* Harvey P. Dale, Aug 20 2019 *)
CROSSREFS
Cf. A143369.
Sequence in context: A264340 A031595 A031775 * A234432 A235677 A235447
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Sep 05 2008
EXTENSIONS
More terms from Colin Barker, Sep 20 2013
STATUS
approved

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Last modified July 25 01:41 EDT 2024. Contains 374585 sequences. (Running on oeis4.)