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 A353582 #15 Jul 09 2022 12:19:05 %S A353582 0,0,2,3,5,13,33,78,186,450,1088,2625,6335,15295,36927,89148,215220, %T A353582 519588,1254398,3028383,7311161,17650705,42612573,102875850,248364270, %U A353582 599604390,1447573052,3494750493,8437074035,20368898563,49174871163,118718640888,286612152936,691942946760 %N A353582 a(n) = 2*a(n-1) + 2*a(n-3) + a(n-4) - 1, with a(0) = 0 = a(1), a(2) = 2, and a(3) = 3. %H A353582 Paul K. Stockmeyer, <a href="/A353582/b353582.txt">Table of n, a(n) for n = 0..1000</a> %H A353582 Andreas M. Hinz and Paul K. Stockmeyer, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL25/Hinz/hinz5.html">Precious Metal Sequences and Sierpinski-Type Graphs</a>, J. Integer Seq., Vol 25 (2022), Article 22.4.8. %H A353582 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2,2,-1,-1). %F A353582 a(n) = (1/16)((4-s)*(1+s)^n + (4+s)*(1-s)^n - 8*sin(n*Pi/2) - 12*cos(n*Pi/2) + 4) where s = sqrt(2). %F A353582 G.f.: x^2*(2 - 3*x)/((1 - x)*(1 + x^2)*(1 - 2*x - x^2)). - _Stefano Spezia_, May 04 2022 %K A353582 nonn,easy %O A353582 0,3 %A A353582 _Paul K. Stockmeyer_, May 04 2022