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a(n) = (9*n + 6)^2.
2

%I #18 Sep 08 2022 08:44:42

%S 36,225,576,1089,1764,2601,3600,4761,6084,7569,9216,11025,12996,15129,

%T 17424,19881,22500,25281,28224,31329,34596,38025,41616,45369,49284,

%U 53361,57600,62001,66564,71289

%N a(n) = (9*n + 6)^2.

%H Vincenzo Librandi, <a href="/A017234/b017234.txt">Table of n, a(n) for n = 0..10000</a>

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

%F From _R. J. Mathar_, Mar 21 2016: (Start)

%F G.f.: ( -36 - 117*x - 9*x^2 ) / (x-1)^3.

%F a(n) = 9*A016790(n). (End)

%o (Magma) [(9*n+6)^2: n in [0..35]]; // _Vincenzo Librandi_, Jul 25 2011

%o (PARI) a(n) = (9*n+6)^2; \\ _Altug Alkan_, Mar 21 2016

%Y Cf. A000290 (n^2), A017233 (9*n+6).

%K nonn,easy

%O 0,1

%A _N. J. A. Sloane_