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A146768
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Number k such that 2^(2k+1) - 1 = A000668(n+1).
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5
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1, 2, 3, 6, 8, 9, 15, 30, 44, 53, 63, 260, 303, 639, 1101, 1140, 1608, 2126, 2211, 4844, 4970, 5606, 9968, 10850, 11604, 22248, 43121, 55251, 66024, 108045, 378419, 429716, 628893, 699134, 1488110, 1510688, 3486296, 6733458, 10498005, 12018291, 12982475, 15201228
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OFFSET
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1,2
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COMMENTS
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The least common multiple of an even superperfect number greater than 2 and its arithmetic derivative divided by the number itself, i.e., lcm(A061652(i), A061652(i)')/A061652(i). - Giorgio Balzarotti, Apr 21 2011
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LINKS
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FORMULA
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MATHEMATICA
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(MersennePrimeExponent[Range[2, 47]] - 1)/2 (* Amiram Eldar, Mar 29 2020 *)
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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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