A292018 - OEIS

%I #10 Feb 09 2024 03:59:20

%S 1,15,44,88,147,221,310,414,533,667,816,980,1159,1353,1562,1786,2025,

%T 2279,2548,2832,3131,3445,3774,4118,4477,4851,5240,5644,6063,6497,

%U 6946,7410,7889,8383,8892,9416,9955,10509,11078,11662,12261,12875,13504,14148,14807,15481

%N Wiener index for the n-Andrásfai graph.

%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/WienerIndex.html">Wiener Index</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).

%F a(n) = (5*n - 4)*(3*n - 1)/2.

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

%F G.f.: (x (-1 - 12 x - 2 x^2))/(-1 + x)^3.

%t Table[(5 n - 4) (3 n - 1)/2, {n, 20}]

%t LinearRecurrence[{3, -3, 1}, {1, 15, 44}, 20]

%t CoefficientList[Series[(-1 - 12 x - 2 x^2)/(-1 + x)^3, {x, 0, 20}], x]

%K nonn,easy

%O 1,2

%A _Eric W. Weisstein_, Sep 07 2017