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A143369 The Szeged index of fourth type dendrimer nanostar which has grown n stages. 1
36604, 304804, 2137492, 13143988, 73561204, 385003252, 1919944180, 9239885812, 43293991924, 198728338420, 897605155828, 4002258869236, 17658743397364, 77238940933108, 335382756072436, 1447262942927860, 6212030751579124, 26540148350000116, 112928927250390004 (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) = 24624*n*4^n + 7156 + 25992*n*2^n + 53532*2^n - 57024*4^n.
G.f.: -4*x*(58624*x^4-138336*x^3+129424*x^2-42762*x+9151) / ((x-1)*(2*x-1)^2*(4*x-1)^2). - Colin Barker, Sep 20 2013
MAPLE
a:=24624*n*4^n+7156+25992*n*2^n+53532*2^n-57024*4^n: seq(a(n), n=1..18);
CROSSREFS
Cf. A143367.
Sequence in context: A011770 A250540 A251797 * A203939 A061739 A232135
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 June 13 05:35 EDT 2024. Contains 373366 sequences. (Running on oeis4.)