

A133376


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


0




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.
The next term has 759 digits.  Harvey P. Dale, Oct 22 2019


LINKS

Table of n, a(n) for n=2..6.


FORMULA

a(n) = 2^(n!/2) for n >= 2.  Karl W. Heuer, Nov 25 2014


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);


MATHEMATICA

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


CROSSREFS

Cf. A124075, A049384.
Sequence in context: A174736 A324567 A135238 * A179056 A160814 A038582
Adjacent sequences: A133373 A133374 A133375 * A133377 A133378 A133379


KEYWORD

nonn


AUTHOR

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


STATUS

approved



