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a(n) = n*(14*n-3).
19

%I #36 Sep 08 2022 08:45:55

%S 0,11,50,117,212,335,486,665,872,1107,1370,1661,1980,2327,2702,3105,

%T 3536,3995,4482,4997,5540,6111,6710,7337,7992,8675,9386,10125,10892,

%U 11687,12510,13361,14240,15147,16082,17045,18036,19055,20102,21177,22280,23411,24570

%N a(n) = n*(14*n-3).

%H Bruno Berselli, <a href="/A185019/b185019.txt">Table of n, a(n) for n = 0..1000</a>

%H Bruno Berselli, <a href="http://www.base5forum.it/upload/A185019.jpg">Illustration of initial terms: An origin of A185019</a>.

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

%F G.f.: x*(11+17*x)/(1-x)^3.

%F a(n) = A195025(-n).

%F a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n >= 3. - _Wesley Ivan Hurt_, Dec 18 2020

%t CoefficientList[Series[x (11 + 17 x)/(1 - x)^3, {x, 0, 45}], x] (*Vincenzo Librandi_, Aug 18 2013 *)

%o (PARI) for(n=0, 42, print1(n*(14*n-3)", "));

%o (Magma) [n*(14*n-3): n in [0..42]];

%o (Magma) I:=[0,11,50]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+Self(n-3): n in [1..50]]; // _Vincenzo Librandi_, Aug 18 2013

%Y Cf. A013656, A049452, A033429, A049453, A147296, A195025.

%Y Cf. A195023, A195024; A000384, A135703.

%Y Cf. A195020 (vertices of the numerical spiral in link).

%K nonn,easy

%O 0,2

%A _Bruno Berselli_, Oct 14 2011 - based on remarks and sequences by _Omar E. Pol_