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 A130773 #12 Apr 20 2025 12:33:26
%S A130773 0,2,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,
%T A130773 49,51,53,55,57,59,61,63,65,67,69,71,73,75,77,79,81,83,85,87,89,91,93,
%U A130773 95,97,99,101,103,105,107,109,111,113,115,117,119,121,123,125,127,129,131,133,135,137,139,141
%N A130773 a(0) = 0, a(1) = 2, a(n) = 2*n + 1 for n >= 2.
%C A130773 Apart from initial term, identical to A140139 if offsets are ignored. - _R. J. Mathar_, May 11 2008
%H A130773 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A130773 O.g.f.: x*(1 + x)*(2 - x)/(1 - x)^2. - _R. J. Mathar_, May 11 2008
%F A130773 E.g.f.: exp(x)*(1 + 2*x) - 1 - x. - _Stefano Spezia_, Apr 20 2025
%t A130773 LinearRecurrence[{2,-1},{0,2,5,7},71] (* _Stefano Spezia_, Apr 20 2025 *)
%Y A130773 Cf. A140139.
%K A130773 nonn,easy
%O A130773 0,2
%A A130773 _Paul Curtz_, Jul 14 2007