%I #7 Sep 20 2018 16:30:35
%S 1,1,1,1,2,2,4,8,12,25,43,94,177,350,702,1413,2954,5963,12333,25625,
%T 53069,111201,232727,489177,1032483,2178467,4617781,9797643,20844394,
%U 44427033,94824892,202789246,434245483,931328024
%N Shifts left 2 places under "BGK" (reversible, element, unlabeled) transform.
%H Andrew Howroyd, <a href="/A032067/b032067.txt">Table of n, a(n) for n = 1..200</a>
%H C. G. Bower, <a href="/transforms2.html">Transforms (2)</a>
%o (PARI)
%o BGK(v)={apply(p->subst(serlaplace(y^0*p + polcoeff(p,1)),y,1)/2, Vec(prod(k=1, #v, (1 + x^k*y + O(x*x^#v))^v[k])-1, -#v))}
%o seq(n)={my(v=vector(2-n%2,i,1)); for(i=1, (n-1)\2, v=concat([1,1], BGK(v))); v} \\ _Andrew Howroyd_, Sep 20 2018
%K nonn
%O 1,5
%A _Christian G. Bower_