A102280 Let k = n-th number == 1 or 5 mod 6 (A007310(n)); consider the generalized 3x+1 map T_k defined by T_k(n) = (3n+k)/2 if n odd, n/2 if n even; then a(n) = smallest positive number m which is in a primitive cycle of T_k.

1, 1, 5, 1, 1, 1, 5, 5, 7, 1, 13, 13, 19, 1, 1, 5, 25, 103, 1, 1, 1, 19, 17, 29, 5, 1, 1, 65, 7, 17, 1, 1, 1, 7, 5, 1, 19, 1, 13, 1, 5, 1, 1, 13, 11, 1, 11, 7, 1, 19, 41, 1, 13, 11, 11, 13, 11, 7, 29, 5, 11, 1, 5, 47, 1, 5, 13, 1, 43, 1, 37, 1, 17, 5, 35, 5, 7, 5, 11, 1, 7, 43, 1, 91, 1, 1, 29, 7, 47, 55, 17, 1, 13

Offset: 1

Author

N. J. A. Sloane, Feb 19 2005

Keywords

• nonn

Links

• Geoffrey H. Morley, Table of n, a(n) for n = 1..10000
• J. C. Lagarias, The set of rational cycles for the 3x+1 problem, Acta Arith. 56 (1990), 33-53. - See Table 3.1 on page 41.

Crossrefs

Cf. A102284, A007310, A226633.

Extensions

a(12)[k=35] and a(25)[k=73] corrected and more terms added by Geoffrey H. Morley, Mar 14 2013