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A111261 Numbers of the form (m/n)^(m-n) with m >=n. 0
1, 2, 4, 8, 9, 16, 32, 64, 81, 128, 256, 512, 625, 729, 1024, 2048, 4096, 6561, 7776, 8192, 16384, 32768, 59049, 65536, 117649, 131072, 262144, 390625, 524288, 531441, 1048576, 2097152, 4194304, 4782969, 8388608, 16777216, 33554432, 43046721 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

All powers of 2 are present, even powers of 3, fourth powers of 5, etc. - Robert G. Wilson v.

LINKS

Table of n, a(n) for n=1..38.

EXAMPLE

The 10th element is a=128 with m = 14 and n =7 because 128 =(14/7)^(14-7).

MAPLE

a:=proc(N) local a, m, n; for m from 1 to N do for n from 1 to m do a:=(m/n)^(m-n); if(floor(a)=a) then print(a) fi; od; od; end: # convert into set # sort set

MATHEMATICA

Take[ Select[ Union[ Flatten[ Table[(m/n)^(m - n), {m, 52}, {n, m}]]], IntegerQ[ # ] &], 40] (* Robert G. Wilson v *)

CROSSREFS

Sequence in context: A113570 A065391 A161792 * A246347 A177404 A046685

Adjacent sequences:  A111258 A111259 A111260 * A111262 A111263 A111264

KEYWORD

nonn

AUTHOR

Paolo P. Lava and Giorgio Balzarotti, Nov 12 2005

EXTENSIONS

Corrected and extended by Robert G. Wilson v, Nov 14 2005

STATUS

approved

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Last modified October 25 02:31 EDT 2014. Contains 248517 sequences.