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A066362
a(n) = least k > n such that phi(k) < phi(n), if such a k exists; otherwise a(n) = 0.
1
0, 0, 0, 0, 6, 0, 8, 0, 10, 0, 12, 0, 14, 0, 18, 18, 18, 0, 20, 0, 22, 24, 24, 0, 26, 30, 28, 30, 30, 0, 32, 36, 34, 36, 36, 0, 38, 40, 40, 42, 42, 0, 44, 48, 46, 48, 48, 0, 50, 54, 52, 54, 54, 60, 56, 60, 58, 60, 60, 0, 62, 66, 64, 66, 66, 0, 68, 70, 70, 0, 72, 0, 74, 78, 76, 78, 78, 0
OFFSET
1,5
COMMENTS
If a(n) = 0, then from n onwards, phi will not go below its value at n.
The first odd term in this sequence is a(314) = 315. - Franklin T. Adams-Watters, Oct 25 2006
EXAMPLE
a(2) = 0 since there is no k > 2 for which phi(k) < 1 = phi(2). a(5) = 6 since for k = 6, phi(6) = 2 < 4 = phi(5).
CROSSREFS
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Dec 20 2001
EXTENSIONS
More terms from Franklin T. Adams-Watters, Oct 25 2006
STATUS
approved