A073889 a(1) = 1, a(2) = 3; for n>2, a(n) = {a(n-1)*a(n+1)}^(1/n) or a(n+1) = a(n)^n/a(n-1).

1, 3, 9, 243, 387420489, 35917545547686059365808220080151141317043

Offset: 1

Author

Amarnath Murthy, Aug 17 2002

Keywords

• nonn

Crossrefs

Cf. A058798, A073888.

Programs

Magma

I:=[1,3]; [n le 2 select I[n] else Self(n-1)^(n-1)/Self(n-2): n in [1..7]]; // G. C. Greubel, May 18 2020

Maple

A073889:= proc(n) option remember;
if n<3 then 2*n-1;
else a(n-1)^(n-1)/a(n-2);
fi; end;
seq(A073889(n), n = 1..7); # G. C. Greubel, May 18 2020

Mathematica

a[n_]:= a[n]= If[n<3, 2*n-1, a[n-1]^(n-1)/a[n-2]]; Table[a[n], {n, 7}] (* G. C. Greubel, May 18 2020 *)

Sage

def a(n):
    if (n<3): return 2*n-1
    else: return a(n-1)^(n-1)/a(n-2)
[a(n) for n in (1..7)] # G. C. Greubel, May 18 2020

Extensions

The next term is too large to include.