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 A187891 #29 Apr 11 2024 10:11:13
%S A187891 0,5,4,8,11,18,28,45,72,116,187,302,488,789,1276,2064,3339,5402,8740,
%T A187891 14141,22880,37020,59899,96918,156816,253733,410548,664280,1074827,
%U A187891 1739106,2813932,4553037,7366968,11920004,19286971,31206974,50493944,81700917
%N A187891 a(0)=0, a(1)=5, a(n)=a(n-1)+a(n-2)-1.
%H A187891 Harvey P. Dale, <a href="/A187891/b187891.txt">Table of n, a(n) for n = 0..1000</a>
%H A187891 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,-1).
%F A187891 a(n) = 1+A022120(n-2), n>2. - _R. J. Mathar_, Mar 15 2011
%F A187891 G.f.: -x^2*(-5+6*x) / ( (x-1)*(x^2+x-1) ). - _R. J. Mathar_, Mar 15 2011
%t A187891 Join[{a=0,b=5},Table[c=a+b-1;a=b;b=c,{n,100}]]
%t A187891 nxt[{a_,b_}]:={b,a+b-1}; NestList[nxt,{0,5},40][[All,1]] (* _Harvey P. Dale_, Nov 03 2022 *)
%Y A187891 Cf. A000071, A001611, A001612, A022120, A187890.
%K A187891 nonn,easy
%O A187891 0,2
%A A187891 _Vladimir Joseph Stephan Orlovsky_, Mar 15 2011