A032320 - OEIS

%I #7 Sep 21 2018 02:22:08

%S 2,2,12,126,1800,33540,757680,20149290,616940520,21378058800,

%T 827126546400,35346832387020,1653593623521840,84055016334088800,

%U 4613207941230688800,271883701342581277950,17125855412989960236600,1148187688612239672677280,81635218693106948988998880

%N Doubles (index 2+) under "EGJ" (unordered, element, labeled) transform.

%H Andrew Howroyd, <a href="/A032320/b032320.txt">Table of n, a(n) for n = 1..200</a>

%H C. G. Bower, <a href="/transforms2.html">Transforms (2)</a>

%o (PARI) EGJ(v)={Vec(serlaplace(prod(k=1, #v, (1 + x^k/k! + O(x*x^#v))^v[k]))-1, -#v)}

%o seq(n)={my(v=[2]); for(i=2, n, v=concat(v, EGJ(concat(v,[0]))[i])); v} \\ _Andrew Howroyd_, Sep 21 2018

%o (PARI) seq(n)={my(p=(1+x)^2 + O(x*x^n)); for(k=2, n, p*=(1 + x^k/k! + O(x*x^n))^(k!*polcoef(p, k))); Vec(x+serlaplace(p-1)/2)} \\ _Andrew Howroyd_, Sep 21 2018

%K nonn

%O 1,1

%A _Christian G. Bower_

%E Terms a(17) and beyond from _Andrew Howroyd_, Sep 21 2018