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 A027083 #24 Jun 01 2025 22:25:40
%S A027083 2,6,14,28,54,102,190,352,650,1198,2206,4060,7470,13742,25278,46496,
%T A027083 85522,157302,289326,532156,978790,1800278,3311230,6090304,11201818,
%U A027083 20603358,37895486,69700668,128199518,235795678,433695870
%N A027083 a(n) = A027082(n, n+2).
%H A027083 Paolo Xausa, <a href="/A027083/b027083.txt">Table of n, a(n) for n = 2..1000</a>
%H A027083 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,0,-1).
%F A027083 G.f.: (2x^2(1+x+x^2))/((1-x)(1-x-x^2-x^3)). Cf. A008937.
%F A027083 a(n) = A027024(n) + 1.
%F A027083 a(n) = A000213(n+3) -3. - _R. J. Mathar_, Jun 24 2020
%t A027083 LinearRecurrence[{2, 0, 0, -1}, {2, 6, 14, 28}, 50] (* _Paolo Xausa_, Sep 16 2024 *)
%Y A027083 Cf. A008937, A027024, A027082.
%K A027083 nonn,easy
%O A027083 2,1
%A A027083 _Clark Kimberling_