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 A038237 #15 Jun 13 2015 00:49:19 %S A038237 1,3,7,26,56,216,462,1791,3828,14849,31735,123111,263108,1020696, %T A038237 2181389,8462447,18085587,70160958,149945056,581694636,1243173370, %U A038237 4822748423,10306975580,39984728949,85453685055,331507764639,708484485384,2748484256480,5873945233705 %N A038237 Second line of 4-wave sequence A038197. %H A038237 Alois P. Heinz, <a href="/A038237/b038237.txt">Table of n, a(n) for n = 0..700</a> %H A038237 F. v. Lamoen, <a href="http://home.wxs.nl/~lamoen/wiskunde/wave.htm">Wave sequences</a> %H A038237 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (0,10,0,-15,0,7,0,-1). %F A038237 G.f.: (x^5+x^4-4*x^3-3*x^2+3*x+1)/(x^8-7*x^6+15*x^4-10*x^2+1). - _Alois P. Heinz_, Jul 16 2009 %p A038237 a:= n-> (Matrix([[26, 7, 3, 1, 0, 0, -1, -1]]). Matrix(8, (i,j)-> if i=j-1 then 1 elif j=1 then [0, 10, 0, -15, 0, 7, 0, -1][i] else 0 fi)^n)[1,4]: seq (a(n), n=0..30); # _Alois P. Heinz_, Jul 16 2009 %K A038237 nonn,easy %O A038237 0,2 %A A038237 _Floor van Lamoen_