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A139802 a(1)=1, a(2)=2, a(n)=n^a(n-2) 1

%I

%S 1,2,3,16,125,2821109907456,

%T 4337654948097993282537354757263188251697832994620405101744893017744569432720994168089672192211758909320807

%N a(1)=1, a(2)=2, a(n)=n^a(n-2)

%C Exponential double factorial.

%C The next term is too large to include.

%e a(1)=1

%e a(2)=2

%e a(3)=3^1=3

%e a(4)=4^2=16

%e a(5)=5^3=125

%e a(6)=6^16=2821109907456

%e etc.

%p P:=proc(n) local a,b,c,i; a:=1; b:=2; print(a); print(b); for i from 3 by 1 to n do c:=i^a; print(c); a:=b; b:=c; od; end: P(10);

%Y Cf. A049384.

%K easy,nonn

%O 0,2

%A _Paolo P. Lava_ and _Giorgio Balzarotti_, May 22 2008

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Last modified July 14 18:26 EDT 2020. Contains 335729 sequences. (Running on oeis4.)