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 A068587 #9 Mar 02 2015 16:08:48 %S A068587 1,2,3,6,6,36,108,3888,23328,90699264,9795520512,888446500935303168, %T A068587 20725679973818752303104,18413657852244156256526524022900467433472, %U A068587 180371363192607497842938699938382286478962971377664 %N A068587 Multiplicative 3-wave sequence starting with 1,2,3. %F A068587 a(n)=a(n-1)*a(n-2) if n is odd, a(n)=a(n-1)*a(n-4) if n is even. %p A068587 For given n, this generates terms with index 0 through 2n: a[0] := 1; a[1] := 2; a[2] := 3; for i from 1 to n-1 do a[2*i+1] := a[2*i]*a[2*i-1]; a[2*i+2] := a[2*i+1]*a[2*i-2]; od; # Christopher N. Swanson (cswanson(AT)ashland.edu), Jul 22 2003 %Y A068587 Cf. A038196. %K A068587 nonn,easy %O A068587 0,2 %A A068587 _Floor van Lamoen_, Mar 21 2002 %E A068587 More terms from Christopher N. Swanson (cswanson(AT)ashland.edu), Jul 22 2003