

A133376


a(n) = (...((2^3)^4)^...)^n.


1




OFFSET

2,1


COMMENTS

Another kind of exponential factorial.
See crossreferences for other possible definitions of exponential factorials.
Some other terms of the sequence can be computed, but they are quite large and it wouldn't be very convenient to display them.


LINKS



FORMULA



EXAMPLE

a(4) = 4096, as (2^3)^4 = 4096.


MAPLE

expfact:= proc(n::integer) local i, res; res:=2; for i from 3 to n do res:=(res)^i od; res end proc; seq(expfact(n), n=2..7);
# second Maple program:
a:= proc(n) option remember;
`if`(n<3, n, a(n1)^n)
end:


MATHEMATICA

nxt[{n_, a_}]:={n+1, a^(n+1)}; NestList[nxt, {2, 2}, 4][[All, 2]] (* Harvey P. Dale, Oct 22 2019 *)


CROSSREFS



KEYWORD

nonn


AUTHOR

Pierre Karpman (pierre.karpman(AT)laposte.net), Oct 28 2007


STATUS

approved



