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 A190961 #31 Jul 29 2025 00:23:14
%S A190961 0,1,3,2,-15,-59,-72,197,1095,1906,-1947,-19183,-43920,2521,315003,
%T A190961 927362,577065,-4760339,-18320472,-21639043,63326175,341451826,
%U A190961 581072253,-646946023,-6008343840,-13496409359,1569178803,99182401922,286562954145,165412048981
%N A190961 a(n) = 3*a(n-1) - 7*a(n-2), with a(0)=0, a(1)=1.
%H A190961 G. C. Greubel, <a href="/A190961/b190961.txt">Table of n, a(n) for n = 0..1000</a>
%H A190961 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-7).
%F A190961 G.f.: x/(1-3*x+7*x^2). - _Philippe Deléham_, Oct 11 2011
%F A190961 E.g.f.: 2*exp(3*x/2)*sin(sqrt(19)*x/2)/sqrt(19). - _Stefano Spezia_, Jul 28 2025
%t A190961 LinearRecurrence[{3,-7}, {0,1}, 50]
%o A190961 (PARI) x='x+O('x^30); concat([0], Vec(x/(1-3*x+7*x^2))) \\ _G. C. Greubel_, Jan 25 2018
%o A190961 (Magma) I:=[0,1]; [n le 2 select I[n] else 3*Self(n-1) - 7*Self(n-2): n in [1..30]]; // _G. C. Greubel_, Jan 25 2018
%Y A190961 Cf. A190958 (index to generalized Fibonacci sequences).
%K A190961 sign,easy
%O A190961 0,3
%A A190961 _Vladimir Joseph Stephan Orlovsky_, May 24 2011