login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A193394 Hyper-Wiener index of a benzenoid consisting of a zig-zag chain of n hexagons (s=13; see the Gutman et al. reference). 7
42, 215, 636, 1513, 3118, 5787, 9920, 15981, 24498, 36063, 51332, 71025, 95926, 126883, 164808, 210677, 265530, 330471, 406668, 495353, 597822, 715435, 849616, 1001853, 1173698, 1366767, 1582740, 1823361, 2090438, 2385843, 2711512, 3069445, 3461706, 3890423, 4357788 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

A. A. Dobrynin, I. Gutman, S. Klavzar, P. Zigert, Wiener Index of Hexagonal Systems, Acta Applicandae Mathematicae 72 (2002), pp. 247-294.

I. Gutman, S. Klavzar, M. Petkovsek, and P. Zigert, On Hosoya polynomials of benzenoid graphs, Comm. Math. Comp. Chem. (MATCH), 43, 2001, 49-66.

Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

FORMULA

a(n) = (8*n^4 + 24*n^3 + 28*n^2 + 147*n - 81)/3.

G.f.: x*(42 + 5*x - 19*x^2 + 63*x^3 - 27*x^4)/(1-x)^5. - Bruno Berselli, Jul 27 2011

MAPLE

a := n-> (8/3)*n^4+8*n^3+(28/3)*n^2+49*n-27: seq(a(n), n = 1 .. 35);

MATHEMATICA

LinearRecurrence[{5, -10, 10, -5, 1}, {42, 215, 636, 1513, 3118}, 40] (* Harvey P. Dale, Dec 10 2021 *)

PROG

(MAGMA) [(8*n^4 + 24*n^3 + 28*n^2 + 147*n - 81)/3: n in [1..40]]; // Vincenzo Librandi, Jul 26 2011

(PARI) a(n)=(8*n^2+24*n+28)*n^2/3+49*n-27 \\ Charles R Greathouse IV, Jul 28 2011

CROSSREFS

Cf. A143937, A143938, A193391, A193392, A193393.

Sequence in context: A122232 A193392 A193400 * A193390 A154472 A221523

Adjacent sequences:  A193391 A193392 A193393 * A193395 A193396 A193397

KEYWORD

nonn,easy

AUTHOR

Emeric Deutsch, Jul 25 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 29 15:27 EDT 2022. Contains 354913 sequences. (Running on oeis4.)