A244634 - OEIS

%I #15 Sep 08 2022 08:46:08

%S 0,27,108,243,432,675,972,1323,1728,2187,2700,3267,3888,4563,5292,

%T 6075,6912,7803,8748,9747,10800,11907,13068,14283,15552,16875,18252,

%U 19683,21168,22707,24300,25947,27648,29403,31212,33075,34992,36963,38988,41067,43200

%N 27*n^2.

%H Vincenzo Librandi, <a href="/A244634/b244634.txt">Table of n, a(n) for n = 0..1000</a>

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

%F G.f.: 27*x*(1 + x)/(1 - x)^3.

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

%F a(n) = 27*A000290(n) = 9*A033428(n) = 3*A016766(n). - _Omar E. Pol_, Jul 03 2014

%t Table[27 n^2, {n, 0, 40}]

%o (Magma) [27*n^2: n in [0..40]];

%o (PARI) a(n)=27*n^2 \\ _Charles R Greathouse IV_, Jun 17 2017

%Y Cf. similar sequences listed in A244630.

%K nonn,easy

%O 0,2

%A _Vincenzo Librandi_, Jul 03 2014

%E G.f. corrected by _Bruno Berselli_, Jul 03 2014