A192790 - OEIS

%I #16 Feb 09 2024 03:58:56

%S 4,80,336,880,1820,3264,5320,8096,11700,16240,21824,28560,36556,45920,

%T 56760,69184,83300,99216,117040,136880,158844,183040,209576,238560,

%U 270100,304304,341280,381136,423980,469920

%N Molecular topological index of the Andrásfai graphs.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/AndrasfaiGraph.html">Andrásfai Graph</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/MolecularTopologicalIndex.html">Molecular Topological Index</a>

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).

%F a(n) = 2*n*(3*n-2)*(3*n-1).

%F a(n) = 4*A006566(n).

%F a(n) = +4*a(n-1) -6*a(n-2) +4*a(n-3) -1*a(n-4).

%F G.f.: 4*x*(1+16*x+10*x^2) / (x-1)^4 . - _R. J. Mathar_, May 06 2014

%t LinearRecurrence[{4,-6,4,-1},{4,80,336,880},30] (* _Harvey P. Dale_, Jan 31 2013 *)

%K nonn,easy

%O 1,1

%A _Eric W. Weisstein_, Jul 10 2011