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 A122574 #40 Oct 30 2024 11:41:56
%S A122574 1,1,-10,111,-1231,13652,-151403,1679085,-18621338,206513803,
%T A122574 -2290273171,25399518684,-281684978695,3123934284329,-34644962106314,
%U A122574 384218517453783,-4261048654097927,47255753712530980,-524074339491938707,5812073488123856757,-64456882708854363034
%N A122574 a(1) = a(2) = 1, a(n) = -11*a(n-1) + a(n-2).
%D A122574 Harry Hochstadt, The Functions of Mathematical Physics, Wiley, New York (1971), p. 170; also Dover, New York (1986), 129-130.
%H A122574 Indranil Ghosh, <a href="/A122574/b122574.txt">Table of n, a(n) for n = 1..958</a>
%H A122574 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>
%H A122574 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (-11,1).
%F A122574 |a(n)| = A049666(n-1) - A049666(n-2), n > 1. [_R. J. Mathar_, Nov 02 2008]
%F A122574 G.f.: x*(1+12*x)/(1+11*x-x^2). [_Philippe Deléham_, Nov 20 2008]
%t A122574 LinearRecurrence[{-11,1},{1,1},30] (* _Harvey P. Dale_, Aug 11 2017 *)
%o A122574 (Magma) [n le 2 select 1 else -11*Self(n-1) +Self(n-2): n in [1..30]]; // _G. C. Greubel_, Oct 30 2024
%o A122574 (SageMath)
%o A122574 A122574=BinaryRecurrenceSequence(-11,1,1,1)
%o A122574 [A122574(n-1) for n in range(1,31)] # _G. C. Greubel_, Oct 30 2024
%Y A122574 Cf. A049666.
%K A122574 sign,easy
%O A122574 1,3
%A A122574 _Roger L. Bagula_, Sep 17 2006
%E A122574 Edited by _N. J. A. Sloane_, Dec 04 2006