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A098475
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a(n) is the smallest integer k for which sigma_n(k) <= sigma_n(k-1) where sigma_n(k) = sum of the n-th powers of the divisors of k.
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1
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3, 5, 7, 25, 61, 145, 361, 853, 1969, 4489, 10069, 22273, 48781, 105949, 228589, 490405, 1046977, 2225965, 4715401, 9956977, 20965213, 44031361, 92262349, 192920785, 402629257, 838827577, 1744784389, 3623814865, 7516104565
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OFFSET
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0,1
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COMMENTS
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a(n) has to be larger than the solution to Zeta(n)*(x-1)^n=x^n.
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LINKS
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EXAMPLE
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a(1)=5 since sigma(1)=1,sigma(2)=3,sigma(3)=4, sigma(4)=7, but sigma(5)=6.
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PROG
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(PARI) a(n) = {my(k = 2); while(sigma(k, n) > sigma(k-1, n), k++); k; } \\ Michel Marcus, Aug 18 2013
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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