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A165623
Integers of the form a(n)=2^n/n^2.
1
2, 1, 1, 4, 256, 4194304, 4503599627370496, 20769187434139310514121985316880384, 1766847064778384329583297500742918515827483896875618958121606201292619776
OFFSET
1,1
EXAMPLE
2^8/8^2=4, .. n :: 1,2,4,8,16,32,64,128,256,512,..
MATHEMATICA
lst={}; Do[i=2^n/n^2; If[IntegerQ[i], AppendTo[lst, i]], {n, 6!}]; lst
PROG
(PARI) a(n)=2^(2^(n-1))/(2^(2*n-2))
CROSSREFS
Sequence in context: A184880 A257859 A231622 * A374358 A264878 A338035
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Program by Charles R Greathouse IV, Oct 12 2009
STATUS
approved