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A133051
Squares of perfect numbers.
1
36, 784, 246016, 66064384, 1125625045712896, 73785850399226331136, 18889393873953262403584, 5316911978187903335626628646131728384, 7067388259113537312203207839508118631205775474686154970915275376716414976
OFFSET
1,1
FORMULA
a(n) = A000396(n)^2
EXAMPLE
a(2)=784 because the second perfect number is 28 and 28^2=784.
MATHEMATICA
Select[Range[9000], DivisorSigma[1, #]== 2*# &]^2 (* G. C. Greubel, Oct 03 2017 *)
CROSSREFS
Cf. A000290, A001248. Perfect numbers: A000396.
Sequence in context: A228331 A014772 A110206 * A215605 A173187 A028222
KEYWORD
nonn
AUTHOR
Omar E. Pol, Oct 30 2007
EXTENSIONS
More terms from Olaf Voß, Feb 13 2008
STATUS
approved