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A225038
Numbers n such that at least one member of Collatz (3x+1) trajectory of n is >= n^2.
0
1, 3, 7, 27, 31, 41, 47, 54, 55, 62, 63, 71, 73, 82, 83, 91, 94, 95, 6631675, 7460635, 319804831, 379027947, 426406441, 479707247, 568541921, 598957743, 639609662, 639609663, 719560871, 758055894, 758055895, 852812882, 852812883, 898436615, 959414494, 959414495, 1010741193, 1079341307, 1137083842, 1137083843, 1410123943
OFFSET
1,2
COMMENTS
Many of these numbers are on the same trajectory. For instance, the numbers from 27 to 95 are all on the Collatz trajectories of 27 and 54. See Roosendaal's web page for more possibilities. - T. D. Noe, Apr 25 2013
FORMULA
Numbers n such that A025586(n) >= n^2.
EXAMPLE
3 is a member since both 16 and 10 both belong to Collatz trajectory of 3 that are >= 3^2 = 9.
MATHEMATICA
Coll[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; t = {}; Do[If[Max[Coll[n]] >= n*n, AppendTo[t, n]], {n, 1000}]; t
CROSSREFS
Sequence in context: A334793 A175198 A272530 * A293564 A056257 A066021
KEYWORD
nonn
AUTHOR
Jayanta Basu, Apr 25 2013
EXTENSIONS
Extended by T. D. Noe, Apr 25 2013
STATUS
approved