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%I #11 Sep 14 2017 17:11:05
%S 1,1,2,48,21233664,1016411962239204484414785454080
%N Quartic recurrence sequence a(0) = 1, a(n) = n*a(n-1)^4.
%C Number of different orderings for n-input trees in a Free Quaternary Decision Diagram.
%C The next term has 121 digits. - _Harvey P. Dale_, Dec 19 2016
%H G. C. Greubel, <a href="/A164334/b164334.txt">Table of n, a(n) for n = 0..7</a>
%F a(0) = 1, a(n) = n*a(n-1)^4.
%t nxt[{n_,a_}]:={n+1,(n+1)a^4}; NestList[nxt,{0,1},5][[All,2]] (* _Harvey P. Dale_, Dec 19 2016 *)
%o (PARI) a(n) = if (n==0, 1, n*a(n-1)^4); \\ _Michel Marcus_, Sep 14 2017
%Y Quartic extension of A052129 and A123851.
%K nonn
%O 0,3
%A David Willingham (D.Willingham(AT)wmin.ac.uk), Aug 13 2009