A095386 Largest prime factor of peak values of 3x+1 trajectory started at n.

2, 2, 2, 2, 2, 13, 2, 13, 2, 13, 2, 5, 13, 5, 2, 13, 13, 11, 5, 2, 13, 5, 3, 11, 5, 577, 13, 11, 5, 577, 2, 5, 13, 5, 13, 7, 11, 19, 5, 577, 2, 7, 13, 17, 5, 577, 3, 37, 11, 29, 13, 5, 577, 577, 7, 7, 11, 19, 5, 23, 577, 577, 2, 7, 5, 19, 17, 13, 5, 577, 3, 577, 7, 17, 11, 29, 19, 101, 5

Offset

2,1

Links

Table of n, a(n) for n=2..80.

Formula

a(n) = A006530(A025586(n)).

Example

n=27: peak = 9232 = 2*2*2*2*577, so a(27)=577;
more extensive search suggests that all primes may occur as largest prime factor of peak.

Crossrefs

Cf. A006530, A025586.

Sequence in context: A088050 A260725 A058005 * A060359 A029665 A256223

Adjacent sequences: A095383 A095384 A095385 * A095387 A095388 A095389

Keyword

nonn

Author

Labos Elemer, Jun 14 2004

Status

approved