This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A063043 #9 Apr 16 2023 23:03:24 %S A063043 17,222,111,37,1148,574,287,41,1518,759,253,23,438,219,73,5184,2592, %T A063043 1296,648,324,162,81,27,9,3,7,36,18,9,3,7,36,18,9,3,7,36,18,9,3,7,36, %U A063043 18,9,3,7,36,18,9,3,7,36,18,9,3,7,36,18,9,3,7,36,18,9,3,7,36 %N A063043 Collatz-2 (A063041) trajectory starting at 17. %C A063043 a(23) = a(28) = 9 and a(i) = a(j) <==> i = j for i, j < 28; same cycle values as A063042 but the conjecture that this is the only cycle for all starting values is not true: see A063044 %F A063043 a(0) = 17 and a(n) = A063041(a(n-1)) for n > 0 %t A063043 NestList[If[PrimeQ[#],#*Prime[PrimePi[#]-1]+1,#/Min@@First/@FactorInteger[#]]&,17,30] (* _Jayanta Basu_, May 27 2013 *) %Y A063043 Cf. A063041, A063042, A063044. %K A063043 easy,nonn %O A063043 0,1 %A A063043 _Reinhard Zumkeller_, Jul 07 2001 %E A063043 More terms from _Sean A. Irvine_, Apr 16 2023