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

1, 2, 4, 32, 262144, 38685626227668133590597632

Offset: 1

Author

Amarnath Murthy, Aug 17 2002

Keywords

• nonn

Crossrefs

Cf. A058798, A073889.

Programs

Magma

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

Maple

A073888:= proc(n) option remember;
if n<3 then n;
else a(n-1)^(n-1)/a(n-2);
fi; end;
seq(A073888(n), n = 1..7); # G. C. Greubel, May 17 2020

Mathematica

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 *)

Sage

def a(n):
    if (n<3): return n
    else: return a(n-1)^(n-1)/a(n-2)
[a(n) for n in (1..7)] # G. C. Greubel, May 17 2020

Formula

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