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 A374192 #19 Jul 14 2024 08:53:27 %S A374192 0,1,1,2,3,2,4,3,7,0,4,3,6,5,7,4,9,8,2,1,7,5,5,4,8,7,11,6,9,8,6,5,11, %T A374192 10,10,9,4,3,12,2,9,8,7,6,13,6,6,5,10,9,16,8,13,12,8,7,10,10,10,9,8,7, %U A374192 9,6,13,12,12,11,11,11,11,10,6,5,14,4,14,13,4,3 %N A374192 Number of iterations required to reach 1 or 10 in a modified Collatz trajectory where x -> x/2 if x is even, x -> x+1 if x is odd and not divisible by 3 and x -> 3x+1 if x is odd and divisible by 3; or a(n) = -1 if 1 or 10 is never reached. %C A374192 It is conjectured that this iteration always reaches one of two cycles [1,2] or [10,5,6,3]. %e A374192 n=1 takes a(1) = 0 iterations to reach 1 or 10, since it's already 1. %e A374192 n=9 takes a(9) = 7 iterations to reach 1, by 9,28,14,7,8,4,2,1. %e A374192 n=15 takes a(15) = 7 iterations to reach 10, by 15,46,23,24,12,6,3,10. %K A374192 nonn %O A374192 1,4 %A A374192 _Gary Detlefs_, Jun 30 2024