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 A280707 Collatz-2 (A063041) trajectory starting at 47. 3
 47, 2022, 1011, 337, 111548, 55774, 27887, 353, 123198, 61599, 20533, 421357694, 210678847, 44385566460664754, 22192783230332377, 1707137171564029, 165918667661, 27529004277737692540278, 13764502138868846270139, 4588167379622948756713, 352935952278688365901, 3237944516318241889, 1577861856421, 2489648037916767181800822 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Will this sequence ever settle into a finite cycle? LINKS Sean A. Irvine, Table of n, a(n) for n = 0..134 (terms 0..41 from Antti Karttunen, terms 42..103 from Hans Havermann) FORMULA a(0) = 47 and for n > 1, a(n) = A063041(a(n-1)). PROG (PARI) A032742(n) = if(1==n, n, n/vecmin(factor(n)[, 1])); A063041(n) = if(2==n, 3, if(isprime(n), 1+(precprime(n-1)*n), A032742(n))); n = 0; k = 47; while(n <= 41, write("b280707.txt", n, " ", k); k = A063041(k); n = n+1); CROSSREFS Cf. A032742, A063041, A063045, A063046. Sequence in context: A202128 A278268 A014941 * A324433 A289984 A189173 Adjacent sequences: A280704 A280705 A280706 * A280708 A280709 A280710 KEYWORD nonn AUTHOR Antti Karttunen, Jan 23 2017 STATUS approved

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Last modified August 13 02:28 EDT 2024. Contains 375113 sequences. (Running on oeis4.)