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A224303 Numbers n for which number of iterations to reach the largest equals number of iterations to reach 1 from the largest in Collatz (3x+1) trajectory of n. 2
1, 6, 120, 334, 335, 804, 1249, 2008, 2010, 2012, 2013, 6556, 6557, 6558, 6801, 6802, 6803, 7496, 7498, 7500, 7501, 7505, 10219, 22633, 25182, 25183, 27074, 27075, 27864, 27866, 27868, 31838, 31839, 32078, 36630, 36633, 36690, 36691, 36914, 39126, 39344 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

For each n here we have A220421(n) = A222641(n).

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

EXAMPLE

6 is in the list because Collatz trajectory of 6 is {6, 3, 10, 5, 16, 8, 4, 2, 1} and number of steps to reach largest = number of steps to reach 1 from largest = 4.

MATHEMATICA

Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3*# + 1] &, n, # > 1 &]; Select[Range[50000], Position[Collatz[#], Max[Collatz[#]]] == {{(Length[Collatz[#]] + 1)/2}} &]

CROSSREFS

Cf. A220421, A222641, A224533 (odd n).

Sequence in context: A178911 A227027 A001219 * A076233 A066581 A054776

Adjacent sequences:  A224300 A224301 A224302 * A224304 A224305 A224306

KEYWORD

nonn

AUTHOR

Jayanta Basu, Apr 03 2013

STATUS

approved

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Last modified January 18 20:57 EST 2019. Contains 319282 sequences. (Running on oeis4.)