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 A057690 Length of cycle in trajectory of P under the `Px+1' map, where P = n-th prime, or -1 if trajectory does not cycle. 8
 3, 3, 4, 4, 3, 4, 4, 5, 4, 6, 3, 4, 4, 6, 5, 5, 3, 4, 6, 3, 6, 5, 5, 4, 4, 5, 6, 4, 4, 8, 5, 4, 5, 5, 5, 3, 4, 6, 4, 6, 4, 8, 3, 5, 6, 4, 7, 5, 4, 5, 7, 4, 6, 4, 6, 6, 6, 3, 12, 4, 5, 5, 6, 3, 4, 4, 4, 5, 5, 4, 7, 6, 4, 5, 9, 5, 3, 4, 4, 6, 3, 8, 4, 6, 5, 6, 3, 5, 6, 6, 8, 5, 5, 6, 7, 5, 5, 4, 3, 4, 5, 5, 5, 5, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS See A057684 for definition. Note that not all cycles for the iteration starting with p contain the number 1; a(60), for the prime 281, is the first example of this. Its iterates are: 281, 78962, 39481, 3037, 853398, 426699, 142233, 47411, 6773, 521, 146402, 73201, 1031, 289712, 144856, 72428, 36214, 18107, 953, 267794, 133897, with the last 12 terms cycling. Another example is provided by 2543, the 372nd prime. - T. D. Noe, Apr 02 2008 LINKS T. D. Noe, Table of n, a(n) for n=2..1000 EXAMPLE For n=3, P=7: trajectory of 7 is 7, 50, 25, 5, 1, 8, 4, 2, 1, 8, 4, 2, 1, 8, 4, 2, 1, ..., which has maximal term 50, cycle length 4 and there are 4 terms before it enters the cycle. CROSSREFS Cf. A057446, A057216, A057522, A057534, A057614. See also A033478, A057688, A057684, A057685, A057686, A057687, A057689, A057691. Sequence in context: A267048 A246011 A061023 * A318706 A298199 A282623 Adjacent sequences:  A057687 A057688 A057689 * A057691 A057692 A057693 KEYWORD nonn,nice,easy AUTHOR N. J. A. Sloane, Oct 20 2000 EXTENSIONS More terms from Larry Reeves (larryr(AT)acm.org), Nov 08 2000 Corrected by T. D. Noe, Apr 02 2008 STATUS approved

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Last modified December 9 20:24 EST 2018. Contains 318023 sequences. (Running on oeis4.)