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 A154327 #16 Feb 01 2023 04:51:29
%S A154327 1,1,2,5,8,15,24,41,66,109,176,287,464,753,1218,1973,3192,5167,8360,
%T A154327 13529,21890,35421,57312,92735,150048,242785,392834,635621,1028456,
%U A154327 1664079,2692536,4356617,7049154,11405773,18454928,29860703,48315632,78176337,126491970,204668309,331160280,535828591,866988872
%N A154327 Diagonal sums of number triangle A132046.
%H A154327 G. C. Greubel, <a href="/A154327/b154327.txt">Table of n, a(n) for n = 0..1000</a>
%H A154327 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,-1,-1).
%F A154327 G.f.: (1 - x^2 + 2x^3 + x^4)/( (1-x^2)*(1-x-x^2) ).
%F A154327 a(n) = 0^n - (3 + (-1)^n)/2 + 2*Fibonacci(n+1).
%t A154327 Join[{1}, LinearRecurrence[{1, 2, -1, -1}, {1, 2, 5, 8}, 25]] (* _G. C. Greubel_, Sep 11 2016 *)
%t A154327 CoefficientList[Series[(1 - x^2 + 2 x^3 + x^4) / ((1 - x^2) (1 - x - x^2)), {x, 0, 50}], x] (* _Vincenzo Librandi_, Sep 12 2016 *)
%o A154327 (Magma) [0^n-(3+(-1)^n)/2+2*Fibonacci(n+1):n in [0..40]]; // _Vincenzo Librandi_, Sep 12 2016
%Y A154327 A shifted version of A066629.
%K A154327 easy,nonn
%O A154327 0,3
%A A154327 _Paul Barry_, Jan 07 2009