[seqfan] (V. Letsko by way of O. Gérard) Two sequences associated with A062401 and A062402
Olivier Gerard
olivier.gerard at gmail.com
Tue May 28 21:33:14 CEST 2013
(due to a technical problem, the original message was not transmitted to
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Hello, seqfans!
Let s(n) = phi(sigma(n))/sigma(phi(n))
1. a(1) = 1, a(n+1) = k, where is the least positive integer such that
s(k) < s(a(n))
The first few members are: 1, 3, 5, 11, 13, 17, 29, 41, 181, 209, 377, 779,
3239, 4469, 5249, 15539...
2. b(1) = 1, b(n+1) = k, where is the least positive integer such that
s(k) > s(b(n))
The first few members are: 1, 2, 36, 144, 576, 3600, 14400, 921600...
--
Best regards,
Vladimir Letsko
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