A135727 Maximal value in orbit of n under the map A001281(x)=3x-1 if x odd, x/2 if x even.

0, 2, 2, 8, 4, 20, 8, 20, 8, 56, 20, 32, 12, 56, 20, 44, 16, 272, 56, 56, 20, 272, 32, 272, 24, 272, 56, 80, 28, 128, 44, 272, 32, 488, 272, 104, 56, 272, 56, 128, 40, 272, 272, 128, 44, 272, 272, 140, 48, 488, 272

Offset

0,2

Comments

On the set of positive integers, the orbit of any number under A001281 seems to end in the orbit of 2, of 20 or of 272, which are the respective maxima of these cycles. Since any odd number increases under the map A001281, all elements of this sequence are even.

Links

Table of n, a(n) for n=0..50.

Prog

(PARI) A135727(n)=local(m=n); if(n, while( n != 272 & n != 20 & n != 2, if( n%2, n=3*n-1; m=max(n, m), n>>=1))); m

Crossrefs

Cf. A001281, A037084, A039500-A039505, A135728-A135730. A006370, A006577.

Sequence in context: A003612 A337944 A103839 * A320423 A274449 A333711

Adjacent sequences: A135724 A135725 A135726 * A135728 A135729 A135730

Keyword

nonn

Author

M. F. Hasler, Nov 26 2007

Status

approved