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A031355 9-multiplicative persistence: number of iterations of "multiply 9th powers of digits" needed to reach 0 or 1. 1
0, 3, 3, 3, 3, 2, 2, 3, 2, 1, 1, 3, 3, 3, 3, 2, 2, 3, 2, 1, 3, 3, 2, 3, 2, 2, 2, 3, 2, 1, 3, 2, 2, 2, 3, 2, 2, 2, 3, 1, 3, 3, 2, 3, 2, 2, 2, 2, 2, 1, 3, 2, 3, 2, 3, 2, 3, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 3, 2, 2, 3, 3, 1, 3, 3, 2, 2, 2, 2, 3, 2, 3, 1, 2, 2, 3, 2, 2, 2, 3, 3, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Multiplicative Persistence
PROG
(Magma) pers:=func<n, e|&*[c^e:c in Intseq(n)]>; a:=[0]; for n in [2..100] do m:=1; k:=n; while not pers(k, 9) in {0, 1} do k:=pers(k, 9); m:=m+1; end while; Append(~a, m); end for; a; // Marius A. Burtea, Jan 13 2020
CROSSREFS
Sequence in context: A081334 A106694 A183051 * A337265 A177228 A247655
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
Offset 1 from Seiichi Manyama, Jan 13 2020
STATUS
approved

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Last modified May 30 04:46 EDT 2024. Contains 372958 sequences. (Running on oeis4.)