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 A295619 #6 Aug 27 2021 21:09:06
%S A295619 1,2,3,4,7,9,16,21,37,50,87,121,208,297,505,738,1243,1853,3096,4693,
%T A295619 7789,11970,19759,30705,50464,79121,129585,204610,334195,530613,
%U A295619 864808,1379037,2243845,3590114,5833959,9358537,15192496,24419961,39612457,63770274
%N A295619 a(n) = a(n-1) + 3*a(n-2) - 2*a(n-3) - 2*a(n-4), where a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4.
%C A295619 a(n)/a(n-1) -> (1 + sqrt(5))/2 = golden ratio (A001622), so that a( ) has the growth rate of the Fibonacci numbers (A000045).
%H A295619 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1, 3, -2, -2)
%F A295619 a(n) = a(n-1) + 3*a(n-2) - 2*a(n-3) - 2*a(n-4), where a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4.
%F A295619 G.f.: (1 + x - 2 x^2 - 3 x^3)/(1 - x - 3 x^2 + 2 x^3 + 2 x^4).
%t A295619 LinearRecurrence[{1, 3, -2, -2}, {1, 2, 3, 4}, 50]
%Y A295619 Cf. A001622, A000045, A295620, A295621.
%K A295619 nonn,easy
%O A295619 0,2
%A A295619 _Clark Kimberling_, Nov 25 2017