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A224462 The hyper-Wiener index of Wang's helicene-based dendrimer defined pictorially as DNS_2[n] in the Shabani et al. reference. 1
5150, 279882, 4912058, 52877106, 437291570, 3075863058, 19424101394, 113690358162, 629297936786, 3338556446610, 17134277121938, 85638400421778, 418886606368658, 2012591878934418, 9525395433164690, 44509034884173714, 205695168792825746 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

H. Shabani, A. R. Ashrafi, I. Gutman, Geometric-arithmetic index: an algebraic approach, Studia UBB, Chemia, LV, 2010, 107-112.

LINKS

Table of n, a(n) for n=1..17.

FORMULA

a(n) = -61550 + 2^n*(30861*n^2 - 164298*n - 602830)+4^n*(59049*n^2 - 677241*n/2 + 664380).

G.f.: 2*x*(2575+91016*x+183400*x^2-872548*x^3-267848*x^4+32480*x^5) / ((1-x)*(1-2*x)^3*(1-4*x)^3).

MAPLE

a := proc (n) options operator, arrow: -61550+2^n*(30861*n^2-164298*n-602830)+4^n*(59049*n^2-(677241/2)*n+664380) end proc: seq(a(n), n = 1 .. 17);

CROSSREFS

Cf. A224461.

Sequence in context: A251244 A188338 A213701 * A251679 A151628 A210400

Adjacent sequences:  A224459 A224460 A224461 * A224463 A224464 A224465

KEYWORD

nonn,easy

AUTHOR

Emeric Deutsch, Jul 12 2013

STATUS

approved

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Last modified February 26 03:10 EST 2021. Contains 341619 sequences. (Running on oeis4.)