A037920 Trajectory of 8 under prime factor concatenation procedure.

8, 2, 2, 2, 2, 3, 37, 3, 19, 41, 3, 3, 3, 7, 13, 13, 3, 11123771, 7, 149, 317, 941, 229, 31219729, 11, 2084656339, 3, 347, 911, 118189, 11, 613, 496501723, 97, 130517, 917327, 53, 1832651281459, 3, 3, 3, 11, 139, 653, 3863, 5107

Offset

0,1

Links

Table of n, a(n) for n=0..45.

Patrick De Geest, Home Primes

Prog

(Python)
from sympy import factorint
def iterate(n):
    flst, f = [n], sorted(factorint(n, multiple=True))
    while len(f) > 1:
        flst += f
        f = sorted(factorint(int("".join(map(str, f))), multiple=True))
    return flst
print(iterate(8)) # Michael S. Branicky, Aug 02 2021

Crossrefs

Cf. A037273, A006919.

Sequence in context: A010150 A176153 A136711 * A138997 A248498 A133918

Adjacent sequences: A037917 A037918 A037919 * A037921 A037922 A037923

Keyword

fini,full,nonn,tabf,base

Author

Jeff Burch

Extensions

Edited by Charles R Greathouse IV, Apr 30 2010

Status

approved