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A106051
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Number of divisors of the Euler number E(2n) (A000364).
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1
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1, 1, 2, 2, 4, 4, 16, 4, 8, 8, 12, 8, 16, 4, 128, 4, 32, 8, 64, 2, 48, 8, 64, 8, 16, 16, 128, 32, 128, 4, 192, 32, 64, 32, 64, 8, 512, 32, 32, 4, 96, 16, 64, 16, 64, 8, 64, 16, 2048, 32, 64, 8, 32, 32, 512, 32, 1024, 64, 32, 16, 96, 16, 512, 256, 2048, 8, 32
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OFFSET
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0,3
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COMMENTS
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Notice that all listed terms are powers of 2 except for the 10th, 20th and 30th. It would be interesting to know whether this pattern continues. Note: Various sources give differing values for the Euler numbers. A000364 gives {1,1,5,61,1385,50521,2702765,199360981,19391512145,...}, whereas Mathematica gives {1,0,-1,0,5,0,-61,0,1385,0,-50521,...}.
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LINKS
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FORMULA
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EXAMPLE
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E(4) = 1385 has divisors {1,5,277,1385}, so a(4) = 4.
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MAPLE
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a:= n-> numtheory[tau](abs(euler(2*n))):
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MATHEMATICA
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a ={}; For[n=0, n<=33, n++, {Eu=EulerE[2*n]; L=Length[Divisors[Eu]]; a=Append[a, L]}]; a
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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