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 A226616 #7 Jul 06 2013 17:20:09 %S A226616 1,5,13,29,11,17,253,509,145,43,55,355,137,1129,1007,131069,97,643,41, %T A226616 553,281,8388605,4069,4793489,3817,1843,59,113,1301,2155,9397,289, %U A226616 131153,3247,949,127,77 %N A226616 Smallest positive integer k for which 1 is in a primitive cycle of n positive integers (n>1) under iteration by the Collatz-like 3x+k function. %C A226616 A cycle is called primitive if its elements are not a common multiple of the elements of another cycle. %C A226616 The 3x+k function T_k is defined by T_k(x) = x/2 if x is even, (3x+k)/2 if x is odd, where k is odd. %C A226616 For primitive cycles, GCD(k,6)=1. %C A226616 For n>1, T_k has a primitive cycle of length n which includes 1 when k = A036563(n) = 2^n-3. So a(n) <= 2^n-3. %Y A226616 Cf. A226607, A226609, A226617, A226618. %K A226616 nonn %O A226616 2,2 %A A226616 _Geoffrey H. Morley_, Jul 02 2013