A039500 -id:A039500 - cp's OEIS frontend

A039504 Odd numbers from A039501.

5, 7, 9, 13, 19, 27, 35, 47, 51, 63, 75, 81, 89, 93, 107, 119, 121, 125, 133, 139, 143, 149, 159, 161, 167, 177, 181, 187, 191, 199, 203, 215, 223, 237, 241, 251, 255, 265, 271, 281, 285, 287, 297, 299, 317, 323, 333, 335, 341, 353, 355, 357, 361, 371, 375

Offset: 1

Christian G. Bower, Feb 15 1999

Cf. A037084, A039500-A039505.

colln[n_]:= NestWhile[If[EvenQ[#], #/2, 3#-1] &, n, FreeQ[{1, 5, 17}, #] &]; Select[Range[1, 375, 2], colln[#] == 5 &] (* Jayanta Basu, Jun 06 2013 *)

A056957 In repeated iterations of function m->m/2 if m even, m->3m-1 if m odd, a(n) is minimum value achieved if starting from n.

Original entry on oeis.org

1, 1, 1, 1, 5, 1, 5, 1, 5, 5, 1, 1, 5, 5, 1, 1, 17, 5, 5, 5, 17, 1, 17, 1, 17, 5, 5, 5, 1, 1, 17, 1, 17, 17, 5, 5, 17, 5, 1, 5, 17, 17, 1, 1, 17, 17, 5, 1, 17, 17, 5, 5, 1, 5, 17, 5, 1, 1, 1, 1, 17, 17, 5, 1, 1, 17, 17, 17, 1, 5, 1, 5, 17, 17, 5, 5, 1, 1, 1, 5, 5, 17, 17, 17, 1, 1, 1, 1, 5, 17

Offset: 1

Henry Bottomley, Jul 18 2000

nonn

At least for n<10000, the only possible cycles reached include 1,2,1,..., 5,14,7,20,10,5,... and 17,50,25,74,37,110,55,164,82,41,122,61,182,91,272,136,68,34,17,... For n<5 only the first occurs, while for n<17 only the first two occur.

			a(9)=5 since iteration starts: 9, 26, 13, 38, 19, 56, 28, 14, 7, 20, 10, 5, 14, 7, 20, 10, 5, ... and 5 is the smallest value

Cf. A001281. If n is in A039500 then a(n)=1, if n is in A039501 then a(n)=5, if n is in A039502 then a(n)=17. If n is negative then this becomes the 3x+1 problem and the minimum values become those which are most negative (i.e. maximum absolute values) as in A056959.

a(2n) = a(n)

Edited by Bryce Herdt (mathidentity(AT)yahoo.com), Apr 18 2010

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A039504 Odd numbers from A039501.

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A056957 In repeated iterations of function m->m/2 if m even, m->3m-1 if m odd, a(n) is minimum value achieved if starting from n.

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