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A033442 Number of edges in 10-partite Turán graph of order n. 10

%I

%S 0,0,1,3,6,10,15,21,28,36,45,54,64,75,87,100,114,129,145,162,180,198,

%T 217,237,258,280,303,327,352,378,405,432,460,489,519,550,582,615,649,

%U 684,720,756,793,831,870,910,951,993,1036,1080,1125,1170,1216,1263

%N Number of edges in 10-partite Turán graph of order n.

%D Graham et al., Handbook of Combinatorics, Vol. 2, p. 1234.

%H Vincenzo Librandi, <a href="/A033442/b033442.txt">Table of n, a(n) for n = 0..1000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TuranGraph.html">Turán Graph</a> [_Reinhard Zumkeller_, Nov 30 2009]

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Tur%C3%A1n_graph">Turán graph</a> [_Reinhard Zumkeller_, Nov 30 2009]

%H <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,0,0,0,0,0,0,0,1,-2,1).

%F a(n) = Sum_{k=0..n} A168184(k)*(n-k). [_Reinhard Zumkeller_, Nov 30 2009]

%F G.f.: -x^2*(x^2+x+1)*(x^6+x^3+1)/((x-1)^3*(x+1)*(x^4-x^3+x^2-x+1)*(x^4+x^3+x^2+x+1)). [_Colin Barker_, Aug 09 2012]

%F a(n) = Sum_{i=1..n} floor(9*i/10). - _Wesley Ivan Hurt_, Sep 12 2017

%t CoefficientList[Series[- x^2 (x^2 + x + 1) (x^6 + x^3 + 1)/((x - 1)^3 (x + 1) (x^4 - x^3 + x^2 - x + 1) (x^4 + x^3 + x^2 + x + 1)), {x, 0, 60}], x] (* _Vincenzo Librandi_, Oct 20 2013 *)

%Y Cf. A002620, A000212, A033436, A033437, A033438, A033439, A033440, A033441, A033443, A033444. [_Reinhard Zumkeller_, Nov 30 2009]

%K nonn,easy

%O 0,4

%A _N. J. A. Sloane_

%E More terms from _Vincenzo Librandi_, Oct 20 2013

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Last modified April 18 12:42 EDT 2019. Contains 322209 sequences. (Running on oeis4.)