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%I #23 Sep 08 2022 08:46:08
%S 1,1,1,1,2,6,48,2592,3421440,1952520007680,79423772100432548659200,
%T 2433694280407609647520301298079459442688000,
%U 1731103819002733625504286414686785477293241305893841298989509923950758461440000
%N a(n) = a(n-1) * (a(n-1) + a(n-2)) / a(n-4) with a(1) = a(2) = a(3) = a(4) = 1.
%H G. C. Greubel, <a href="/A245283/b245283.txt">Table of n, a(n) for n = 1..17</a>
%F a(n+3) = a(n+2) * A245384(n) for n>0.
%t a[ n_] := If[ n<5, 1, a[n] = a[n-1] (a[n-1] + a[n-2]) / a[n-4]];
%t RecurrenceTable[{a[n] == a[n-1]*(a[n-1] + a[n-2])/a[n-4], a[1] == a[2] == a[3] == a[4] == 1}, a, {n, 1, 10}] (* _G. C. Greubel_, Aug 06 2018 *)
%t nxt[{a_,b_,c_,d_}]:={b,c,d,d (d+c)/a}; NestList[nxt,{1,1,1,1},15][[All,1]] (* _Harvey P. Dale_, Jun 25 2021 *)
%o (PARI) {a(n) = if( n<5, 1, a(n-1) * (a(n-1) + a(n-2)) / a(n-4))};
%o (Magma) I:=[1,1,1,1]; [n le 4 select I[n] else Self(n-1)*(Self(n-1) + Self(n-2))/Self(n-4): n in [1..10]]; // _G. C. Greubel_, Aug 06 2018
%Y Cf. A245384.
%K nonn
%O 1,5
%A _Michael Somos_, Aug 21 2014
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