login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A292282 a(n) = 2*(n-1)^3*n^2*(n+1). 1
0, 24, 576, 4320, 19200, 63000, 169344, 395136, 829440, 1603800, 2904000, 4983264, 8176896, 12918360, 19756800, 29376000, 42614784, 60488856, 84214080, 115231200, 155232000, 206186904, 270374016, 350409600, 449280000, 570375000, 717522624, 895025376, 1107697920 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Molecular topological index of the n X n rook complement graph for n != 2.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..5000

Eric Weisstein's World of Mathematics, Molecular Topological Index

Eric Weisstein's World of Mathematics, Rook Complement Graph

Index entries for linear recurrences with constant coefficients, signature (7, -21, 35, -35, 21, -7, 1).

FORMULA

a(n) = 2*(n-1)^3*n^2*(n+1).

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7).

G.f.: -24*x^2*(1 + 17*x + 33*x^2 + 9*x^3)/(-1 + x)^7.

MATHEMATICA

Table[2 (-1 + n)^3 n^2 (1 + n), {n, 20}]

LinearRecurrence[{7, -21, 35, -35, 21, -7, 1}, {0, 24, 576, 4320, 19200, 63000, 169344}, 30]

CoefficientList[Series[-24 x (1 + 17 x + 33 x^2 + 9 x^3)/(-1 + x)^7, {x, 0, 20}], x]

PROG

(PARI) a(n)=2*(n-1)^3*n^2*(n+1) \\ Charles R Greathouse IV, Sep 14 2017

(MAGMA) [2*(n-1)^3*n^2*(n+1): n in [1..30]]; // G. C. Greubel, Dec 12 2017

CROSSREFS

Sequence in context: A077423 A059061 A206991 * A206933 A206868 A181221

Adjacent sequences:  A292279 A292280 A292281 * A292283 A292284 A292285

KEYWORD

nonn,easy

AUTHOR

Eric W. Weisstein, Sep 14 2017

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 18 22:08 EDT 2019. Contains 322237 sequences. (Running on oeis4.)