This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A041403 #20 Jul 09 2025 00:46:39 %S A041403 1,1,3,10,23,33,947,980,2907,9701,22309,32010,918589,950599,2819787, %T A041403 9409960,21639707,31049667,891030383,922080050,2735190483,9127651499, %U A041403 20990493481,30118144980,864298552921,894416697901,2653131948723,8853812544070,20360757036863 %N A041403 Denominators of continued fraction convergents to sqrt(216). %H A041403 Vincenzo Librandi, <a href="/A041403/b041403.txt">Table of n, a(n) for n = 0..200</a> %H A041403 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,970,0,0,0,0,0,-1). %F A041403 G.f.: -(x^10 -x^9 +3*x^8 -10*x^7 +23*x^6 -33*x^5 -23*x^4 -10*x^3 -3*x^2 -x -1) / ((x^4 -10*x^2 +1)*(x^8 +10*x^6 +99*x^4 +10*x^2 +1)). - _Colin Barker_, Nov 17 2013 %F A041403 a(n) = 970*a(n-6) - a(n-12) for n>11. - _Vincenzo Librandi_, Dec 17 2013 %t A041403 Denominator[Convergents[Sqrt[216], 30]] (* _Vincenzo Librandi_, Dec 17 2013 *) %o A041403 (Magma) I:=[1,1,3,10,23,33,947,980,2907,9701,22309, 32010]; [n le 12 select I[n] else 970*Self(n-6)-Self(n-12): n in [1..40]]; // _Vincenzo Librandi_, Dec 17 2013 %Y A041403 Cf. A041402, A040201. %K A041403 nonn,frac,easy %O A041403 0,3 %A A041403 _N. J. A. Sloane_ %E A041403 More terms from _Colin Barker_, Nov 17 2013