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 A107389 #21 Jun 07 2025 04:09:35
%S A107389 0,1,-1,2,5,31,144,697,3335,15986,76589,366967,1758240,8424241,
%T A107389 40362959,193390562,926589845,4439558671,21271203504,101916458857,
%U A107389 488311090775,2339638995026,11209883884349,53709780426727,257339018249280,1232985310819681,5907587535849119
%N A107389 Expansion of x*(1-6*x+7*x^2)/( (1-x)*(1+x)*(1-5*x+x^2)).
%H A107389 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (5,0,-5,1).
%F A107389 a(n)-a(n-2) = A030221(n-3), n>2. - _R. J. Mathar_, Dec 17 2017
%t A107389 LinearRecurrence[{5,0,-5,1},{0,1,-1,2},30] (* _Harvey P. Dale_, Sep 17 2020 *)
%o A107389 (PARI) concat(0,Vec((1-6*x+7*x^2)/(1-x)/(1+x)/(1-5*x+x^2)+O(x^98))) \\ _Charles R Greathouse IV_, Jan 25 2012
%K A107389 sign,easy
%O A107389 0,4
%A A107389 _Roger L. Bagula_, May 24 2005, corrected Sep 04 2008
%E A107389 Irregular sign at a(2) switched by R. J. Mathar, Jan 24 2012