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A360806
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a(0) = 1; for n >= 1, a(n) is the least integer k > a(n-1) such that k / A000005(k) = a(n-1).
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2
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OFFSET
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0,2
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LINKS
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EXAMPLE
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a(0) = 1.
a(1) = 2 because the least k > 1 such that k / A000005(k) = 1 is k = 2.
a(2) = 8 because the least k > 2 such that k / A000005(k) = 2 is k = 8.
a(3) = 80 because the least k > 8 such that k / A000005(k) = 8 is k = 80.
and so on.
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MATHEMATICA
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a[0] = 1; a[n_] := a[n] = Module[{m = a[n - 1], k}, k = 2*m; While[k != m*DivisorSigma[0, k], k += m]; k]; Array[a, 9, 0] (* Amiram Eldar, Feb 21 2023 *)
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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