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A061193
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Number of digits in n-th even perfect number (A000396).
(Formerly N0213)
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3
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1, 2, 3, 4, 8, 10, 12, 19, 37, 54, 65, 77, 314, 366, 770, 1327, 1373, 1937, 2561, 2663, 5834, 5985, 6751, 12003, 13066, 13973, 26790, 51924, 66530, 79502, 130100, 455663, 517430, 757263, 841842, 1791864, 1819050, 4197919, 8107892, 12640858, 14471465, 15632458, 18304103, 19616714, 22370543
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OFFSET
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1,2
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COMMENTS
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The next known values following a(47) are 34850340, 44677235 and 46498850, but these may not be the next terms. [Updated by M. F. Hasler, Nov 28 2017, Ivan Panchenko, Apr 07 2018, Apr 17 2018]
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REFERENCES
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A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 19.
Martin Gardner, Mathematical Magic Show. Alfred A. Knopf. 1977 p. 165
Paul Hoffman, Archimedes' Revenge. Penguin. 1988 p. 11
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
Donald D. Spencer, Key Dates in Number Theory History. Camelot Pub.Co. 1995 p. 80.
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LINKS
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FORMULA
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MATHEMATICA
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Table[n=MersennePrimeExponent@k; IntegerLength[2^(n-1)(2^n-1)], {k, 45}] (* Giorgos Kalogeropoulos, Sep 03 2020 *)
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PROG
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(PARI) apply( p->(2*p-1)*log(2)\log(10)+1, A000043) \\ where A000043 is the vector of the known Mersenne primes. - M. F. Hasler, Nov 28 2017
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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