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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 (list; graph; refs; listen; history; text; internal format)
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

LINKS

Table of n, a(n) for n=1..41.

Eric Roosendaal, 3x+1 path records

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

Cf. A025586, A070165.

Sequence in context: A305446 A175198 A272530 * A293564 A056257 A066021

Adjacent sequences:  A225035 A225036 A225037 * A225039 A225040 A225041

KEYWORD

nonn

AUTHOR

Jayanta Basu, Apr 25 2013

EXTENSIONS

Extended by T. D. Noe, Apr 25 2013

STATUS

approved

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Last modified July 17 23:21 EDT 2019. Contains 325109 sequences. (Running on oeis4.)