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A354567
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a(n) is the least number k such that P(k)^n | k and P(k+1)^n | (k+1), where P(k) = A006530(k) is the largest prime dividing k, or -1 if no such k exists.
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0
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OFFSET
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1,2
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COMMENTS
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a(1) = 1 since P(1) = 1 by convention. Without this convention we would have a(1) = 2.
a(5) <= 437489361912143559513287483711091603378 (De Koninck, 2009).
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LINKS
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EXAMPLE
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a(2) = 8 since 8 = 2^3, P(8) = 2 and 2^2|8, 9 = 3^2, P(9) = 3 and 3^2 | 9, and 8 is the least number with this property.
a(3) = 6859 since 6859 = 19^3, P(6859) = 19 and 19^3 | 6859, 6860 = 2^2 * 5 * 7^3, P(6860) = 7 and 7^3 | 6860, and 6859 is the least number with this property.
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CROSSREFS
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KEYWORD
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nonn,more,bref
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AUTHOR
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STATUS
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approved
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