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A139802 a(1)=1, a(2)=2, a(n)=n^a(n-2) +0
2
1, 2, 3, 16, 125, 2821109907456, 43376549480979932825373547572631882516978329946204051017448930177445694327209941\ 68089672192211758909320807 (list; graph; listen)
OFFSET

0,2

COMMENT

Exponential double factorial.

The next term is too large to include.

EXAMPLE

a(1)=1

a(2)=2

a(3)=3^1=3

a(4)=4^2=16

a(5)=5^3=125

a(6)=6^16=2821109907456

etc.

MAPLE

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);

CROSSREFS

Cf. A049384.

Sequence in context: A007118 A012572 A067848 this_sequence A063666 A006247 A052318

Adjacent sequences: A139799 A139800 A139801 this_sequence A139803 A139804 A139805

KEYWORD

easy,nonn

AUTHOR

Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), May 22 2008

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.


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