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A266269
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a(n) is the smallest number k such that phi(k) >= n*phi(k-1).
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1
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(3) = 7 because 7 is the smallest number k such that phi(k) >= n*phi(k-1); phi(7) = 6 >= 3*phi(6) = 3*2.
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PROG
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(Magma) a:=func<n | exists(r){k:k in[2..10^7] | Floor(EulerPhi(k) / EulerPhi(k-1)) eq n}select r else 0>; [a(n):n in[1..5]]
(PARI) a(n) = {my(k=2, e=1); while(n*e > e=eulerphi(k), k++); k; } \\ Jinyuan Wang, Nov 01 2020
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CROSSREFS
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Cf. A000010 (phi), A266276 (the smallest k such that phi(k) = n*phi(k-1)).
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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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