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 A038341 #11 Apr 10 2022 14:34:40 %S A038341 1,2,14,29,175,365,2163,4516,26703,55759,329615,688286,4068623, %T A038341 8495917,50221212,104869718,619907431,1294463368,7651850657, %U A038341 15978257251,94450905714,197228218022,1165858298498,2434493909304,14390815650209 %N A038341 Fourth line of 5-wave sequence A038201. %H A038341 F. v. Lamoen, <a href="http://home.wxs.nl/~lamoen/wiskunde/wave.htm">Wave sequences</a> %F A038341 G.f.: (x^3+x^2-2*x-1) / (x^10-9*x^8+28*x^6-35*x^4+15*x^2-1). - _Alois P. Heinz_, Jul 16 2009 %p A038341 a:= n-> (Matrix([[`if`(irem(n,2)=0, 1, 2), 0, 0, 0, -1]]). Matrix(5, (i,j)-> if i=j-1 then 1 elif j=1 then [15, -35, 28, -9, 1][i] else 0 fi) ^iquo(n, 2))[1,1]: seq(a(n), n=0..30); # _Alois P. Heinz_, Jul 16 2009 %Y A038341 Cf. A038201. %K A038341 nonn,easy %O A038341 0,2 %A A038341 _Floor van Lamoen_ %E A038341 More terms from _Alois P. Heinz_, Jul 16 2009