A066362 a(n) = least k > n such that phi(k) < phi(n), if such a k exists; otherwise a(n) = 0.

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

Author

Joseph L. Pe, Dec 20 2001

Keywords

• nonn

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

Examples

			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

Cf. A000010, A036912, A036913.

Extensions

More terms from Franklin T. Adams-Watters, Oct 25 2006