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 A073888 a(1) = 1, a(2) = 2; a(n+1) = a(n)^n/a(n-1). 3

%I

%S 1,2,4,32,262144,38685626227668133590597632

%N a(1) = 1, a(2) = 2; a(n+1) = a(n)^n/a(n-1).

%F a(n) = 2^A058798(n).

%p A073888:= proc(n) option remember;

%p if n<3 then n;

%p else a(n-1)^(n-1)/a(n-2);

%p fi; end;

%p seq(A073888(n), n = 1..7); # _G. C. Greubel_, May 17 2020

%t a[n_]:= a[n]= If[n<3, n, a[n-1]^(n-1)/a[n-2]]; Table[a[n], {n, 7}] (* _G. C. Greubel_, May 17 2020 *)

%o (Magma)

%o I:=[1,2]; [n le 2 select I[n] else Self(n-1)^(n-1)/Self(n-2): n in [1..7]]; // _G. C. Greubel_, May 17 2020

%o (Sage)

%o def a(n):

%o if (n<3): return n

%o else: return a(n-1)^(n-1)/a(n-2)

%o [a(n) for n in (1..7)] # _G. C. Greubel_, May 17 2020

%Y Cf. A058798, A073889.

%K nonn

%O 1,2

%A _Amarnath Murthy_, Aug 17 2002

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Last modified November 30 03:03 EST 2021. Contains 349416 sequences. (Running on oeis4.)