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A266276
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a(n) is the smallest number k such that phi(k) = n*phi(k-1).
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3
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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..10^8] | EulerPhi(k) eq n*EulerPhi(k-1)}select r else 0>; [a(n):n in[1..5]]
(PARI) a(n) = my(k=2, epk=1, enk); while ((enk=eulerphi(k)) != n*epk, epk = enk; k++); k; \\ Michel Marcus, Feb 20 2020
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CROSSREFS
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Cf. A000010 (phi(n)), A266269 (the smallest numbers 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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STATUS
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approved
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