[seqfan] Numbers n such that phi(n)/phi(phi(n)) > phi(m)/phi(phi(m)) for all m < n

David Corneth davidacorneth at gmail.com
Sun Jun 25 21:41:12 CEST 2017


Hi all,
This is about https://oeis.org/A289125.
phi(a(i)) is divisible by mostly consecutive first primes; the prime
factorizations of the found terms are:
1
2^1
2^1 * 3^1
2^1 * 3^1 * 5^1
2^1 * 3^1 * 5^1 * 7^1
2^1 * 3^1 * 5^1 * 7^1 * 11^1
2^1 * 3^1 * 5^1 * 7^1 * 11^1 * 19^1
2^2 * 3^1 * 5^1 * 7^1 * 11^1 * 13^1
2^1 * 3^1 * 5^1 * 7^1 * 11^1 * 13^1 * 29^1
2^2 * 3^1 * 5^1 * 7^1 * 11^1 * 13^1 * 17^1
2^1 * 3^1 * 5^1 * 7^1 * 11^1 * 13^1 * 19^1 * 23^1
2^2 * 3^1 * 5^1 * 7^1 * 11^1 * 13^1 * 17^1 * 19^1
2^1 * 3^1 * 5^1 * 7^1 * 11^1 * 13^1 * 17^1 * 19^1 * 31^1
2^2 * 3^1 * 5^1 * 7^1 * 11^1 * 13^1 * 17^1 * 19^1 * 23^1
Which relates the sequence somewhat to A002110 <https://oeis.org/A002110>
 right?



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