A280707 Collatz-2 (A063041) trajectory starting at 47.

47, 2022, 1011, 337, 111548, 55774, 27887, 353, 123198, 61599, 20533, 421357694, 210678847, 44385566460664754, 22192783230332377, 1707137171564029, 165918667661, 27529004277737692540278, 13764502138868846270139, 4588167379622948756713, 352935952278688365901, 3237944516318241889, 1577861856421, 2489648037916767181800822

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