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 A123231 #26 Sep 08 2022 08:45:28
%S A123231 1,2,1,3,2,5,3,8,5,13,8,21,13,34,21,55,34,89,55,144,89,233,144,377,
%T A123231 233,610,377,987,610,1597,987,2584,1597,4181,2584,6765,4181,10946,
%U A123231 6765,17711,10946,28657,17711,46368,28657,75025,46368,121393,75025,196418
%N A123231 Row sums of A123230.
%C A123231 All terms are Fibonacci numbers A000045: a(2n-1) = Fibonacci(n), a(2n) = Fibonacci(n+2), a(2n-1) = a(2n+2). - _Alexander Adamchuk_, Oct 08 2006
%H A123231 G. C. Greubel, <a href="/A123231/b123231.txt">Table of n, a(n) for n = 1..1000</a>
%H A123231 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,1,0,1).
%F A123231 From _Alexander Adamchuk_, Oct 08 2006: (Start)
%F A123231 a(n) = Fibonacci(A028242(n+2)).
%F A123231 a(n) = Fibonacci(A030451(n+1)).
%F A123231 a(n) = Fibonacci(3/4 -(-1)^(n+1)*3/4 +(n+1)/2). (End)
%F A123231 a(n) = A053602(n+1) = A097594(n-5). - _R. J. Mathar_, Mar 08 2011
%F A123231 G.f. -x*(1+2*x+x^3) / ( -1+x^2+x^4 ). - _R. J. Mathar_, Mar 08 2011
%F A123231 a(n) = a(n-2) + a(n-4). - _Muniru A Asiru_, Oct 12 2018
%p A123231 seq(coeff(series(-x*(1+2*x+x^3)/(x^4+x^2-1),x,n+1), x, n), n = 1 .. 50); # _Muniru A Asiru_, Oct 12 2018
%t A123231 p[0, x] = 1; p[1, x] = x + 1; p[k_, x_] := p[k, x] = x*p[k - 1, x] + (-1)^(n + 1)p[k - 2, x]; Table[Sum[CoefficientList[p[n, x], x][[m]], {m, 1, n + 1}], {n, 0, 20}]
%t A123231 Rest[Flatten[Reverse/@Partition[Fibonacci[Range[30]],2,1]]] (* _Harvey P. Dale_, Mar 19 2013 *)
%o A123231 (PARI) vector(50, n, fibonacci(3/4 -(-1)^(n+1)*3/4 +(n+1)/2)) \\ _G. C. Greubel_, Oct 12 2018
%o A123231 (Magma) m:=50; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(x*(1 + 2*x + x^3)/(1 - x^2 - x^4))); // _G. C. Greubel_, Oct 12 2018
%o A123231 (GAP) a:=[1,2,1,3];; for n in [5..50] do a[n]:=a[n-2]+a[n-4]; od; a; # _Muniru A Asiru_, Oct 12 2018
%Y A123231 Cf. A051792, A000045, A028242, A030451.
%K A123231 nonn
%O A123231 1,2
%A A123231 _Roger L. Bagula_, Oct 06 2006
%E A123231 More terms from _Alexander Adamchuk_, Oct 08 2006