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 A099484 #14 Jun 17 2020 11:39:35
%S A099484 1,1,2,7,19,48,125,329,862,2255,5903,15456,40465,105937,277346,726103,
%T A099484 1900963,4976784,13029389,34111385,89304766,233802911,612103967,
%U A099484 1602508992,4195423009,10983760033,28755857090,75283811239,197095576627
%N A099484 A Fibonacci convolution.
%C A099484 A Chebyshev transform of the sequence 1,1,3,9,27 with g.f. (1-2x)/(1-3x). The image of G(x) under the Chebyshev transform is (1/(1+x^2))G(x/(1+x^2)).
%H A099484 Harvey P. Dale, <a href="/A099484/b099484.txt">Table of n, a(n) for n = 0..1000</a>
%H A099484 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2,3,-1).
%F A099484 G.f.: (1-x)^2/((1+x^2)*(1-3*x+x^2)), convolution of A176742 and A001906.
%F A099484 a(n)=3a(n-1)-2a(n-2)+3a(n-3);
%F A099484 a(n)=sum{k=0..floor(n/2), binomial(n-k, k)(-1)^n*(3^(n-2k)+2*0^(n-2k))/3};
%F A099484 a(n)=sum{k=0..n, (0^k-2sin(pi*k/2))F(2(n-k)+2)}.
%F A099484 (1/3) [Fib(2n+2) + I^n + (-I)^n ]. - _Ralf Stephan_, Dec 04 2004
%F A099484 3*a(n) = A001906(n+1) +2*A056594(n). - _R. J. Mathar_, Jun 17 2020
%t A099484 LinearRecurrence[{3,-2,3,-1},{1,1,2,7},40] (* _Harvey P. Dale_, Mar 25 2020 *)
%Y A099484 Cf. A000045, A099483, A099485.
%K A099484 easy,nonn
%O A099484 0,3
%A A099484 _Paul Barry_, Oct 18 2004