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 A038261 #12 Jun 13 2015 00:49:19 %S A038261 1,5,55,671,8272,102091,1260143,15554592,191998646,2369942427, %T A038261 29253473175,361091343583,4457144547354,55016930950608, %U A038261 679103551405906,8382540166524150,103470199055689961,1277188284212361415 %N A038261 First line of 5-wave sequence A038201, also bisection of A006358. %H A038261 F. v. Lamoen, <a href="http://home.wxs.nl/~lamoen/wiskunde/wave.htm">Wave sequences</a> %H A038261 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (15,-35,28,-9,1). %F A038261 Conjecture: GF = -(x-1)*(x^3-6*x^2+9*x-1) / ( -1+15*x-35*x^2+28*x^3-9*x^4+x^5 ). - _Wouter Meeussen_, Mar 19 2005 %p A038261 a:= n-> (Matrix([[5, 1, 1, 2, 5]]). Matrix(5, (i,j)-> if i=j-1 then 1 elif j=1 then [15, -35, 28, -9, 1][i] else 0 fi)^n)[1,2]: seq(a(n), n=0..20); # _Alois P. Heinz_, Jul 16 2009 %K A038261 nonn,easy %O A038261 0,2 %A A038261 _Floor van Lamoen_