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%I #33 Sep 08 2022 08:46:08
%S 0,17,68,153,272,425,612,833,1088,1377,1700,2057,2448,2873,3332,3825,
%T 4352,4913,5508,6137,6800,7497,8228,8993,9792,10625,11492,12393,13328,
%U 14297,15300,16337,17408,18513,19652,20825,22032,23273,24548,25857,27200
%N a(n) = 17*n^2.
%C First bisection of A195047. - _Bruno Berselli_, Jul 03 2014
%C Norms of purely imaginary numbers in Z[sqrt(-17)] (for example, 3*sqrt(-17) has norm 153). - _Alonso del Arte_, Jun 23 2018
%H Vincenzo Librandi, <a href="/A244630/b244630.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.: 17*x*(1 + x)/(1 - x)^3. [corrected by _Bruno Berselli_, Jul 03 2014]
%F a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 2.
%F a(n) = 17*A000290(n). - _Omar E. Pol_, Jul 03 2014
%F a(n) = a(-n). - _Muniru A Asiru_, Jun 29 2018
%p seq(17*n^2,n=0..45); # _Muniru A Asiru_, Jun 29 2018
%t Table[17 n^2, {n, 0, 40}]
%o (Magma) [17*n^2: n in [0..40]];
%o (PARI) a(n)=17*n^2 \\ _Charles R Greathouse IV_, Oct 07 2015
%o (GAP) List([0..45],n->17*n^2); # _Muniru A Asiru_, Jun 29 2018
%o (Scala) for (i <- 0 to 50) yield 17 * (i * i) // _Alonso del Arte_, Jun 29 2018
%Y Cf. A195047.
%Y Cf. similar sequences of the type k*n^2: A000290 (k = 1), A001105 (k = 2), A033428 (k = 3), A016742 (k = 4), A033429 (k = 5), A033581 (k = 6), A033582 (k = 7), A139098 (k = 8), A016766 (k = 9), A033583 (k = 10), A033584 (k = 11), A135453 (k = 12), A152742 (k = 13), A144555 (k = 14), A064761 (k = 15), A016802 (k = 16), this sequence (k = 17), A195321 (k = 18), A244631 (k = 19), A195322 (k = 20), A064762 (k = 21), A195323 (k = 22), A244632 (k = 23), A195824 (k = 24), A016850 (k = 25), A244633 (k = 26), A244634 (k = 27), A064763 (k = 28), A244635 (k = 29), A244636 (k = 30).
%K nonn,easy
%O 0,2
%A _Vincenzo Librandi_, Jul 03 2014
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