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 A042891 #18 Jan 27 2020 01:22:32 %S A042891 1,3,4,35,179,214,393,1393,10144,11537,21681,163304,511593,674897, %T A042891 1186490,6607347,54045266,60652613,236003105,14692845123,44314538474, %U A042891 59007383597,516373607250,2640875419847,3157249027097 %N A042891 Denominators of continued fraction convergents to sqrt(977). %C A042891 The Hankel transform (see A001906 for definition) of this sequence forms the sequence A047656(n+1)= [1,3,27,729,59049,14348907,...] . - _Philippe Deléham_, Aug 29 2006 %H A042891 Harvey P. Dale, <a href="/A042891/b042891.txt">Table of n, a(n) for n = 0..1000</a> %H A042891 <a href="/index/Rec#order_38">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14753497736, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1). %F A042891 The Hankel transform (see A001906 for definition) of this sequence forms the sequence A047656(n+1)= [1,3,27,729,59049,14348907,...]. - _Philippe Deléham_, Aug 29 2006 %F A042891 a(n) = 14753497736*a(n-19) - a(n-38) for n > 37. - _Vincenzo Librandi_, Jan 31 2014 %t A042891 Denominator[Convergents[Sqrt[977], 40]] (* _Harvey P. Dale_, May 09 2012 *) %Y A042891 Cf. A042890, A040945. %K A042891 nonn,frac,easy %O A042891 0,2 %A A042891 _N. J. A. Sloane_