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 A108176 #12 Aug 17 2017 22:32:03
%S A108176 1,1,1,2,3,7,23,164,3786,620973,2351006074,1459911295051236,
%T A108176 3432260322166663402961472,5010795611887306064313121202903094714708,
%U A108176 17198354961167628388233455836547370709483687001035342768448084064
%N A108176 a(1) = 1, a(n) = (Sum_{k=1..floor(n/2)} 1/a(n + 1 - 2k))*(Product_{k=1..floor(n/2)} a(n + 1 - 2k)).
%F A108176 For n >= 2, a(n+4) = a(n+1)*(a(n+2) - a(n)a(n+1)) + a(n+2)a(n+3).
%p A108176 a[1]:=1: for n from 2 to 25 do a[n]:=sum(1/a[n+1-2*j],j=1..floor(n/2))*product(a[n+1-2*k],k=1..floor(n/2)) od: seq(a[n],n=1..16); # _Emeric Deutsch_, Jun 14 2005
%t A108176 a[1] = 1; a[n_] := a[n] = Sum[1/a[n + 1 - 2k], {k, Floor[n/2]}] Product[ a[n + 1 - 2k], {k, Floor[n/2]}]; Table[ a[n], {n, 15}] (* _Robert G. Wilson v_, Jun 14 2005 *)
%Y A108176 Cf. A057438.
%K A108176 nonn
%O A108176 1,4
%A A108176 _Leroy Quet_, Jun 13 2005
%E A108176 More terms from _Robert G. Wilson v_ and _Emeric Deutsch_, Jun 14 2005