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 A031355 9-multiplicative persistence: number of iterations of "multiply 9th powers of digits" needed to reach 0 or 1. 1

%I #15 Sep 08 2022 08:44:50

%S 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,

%T 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,

%U 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

%N 9-multiplicative persistence: number of iterations of "multiply 9th powers of digits" needed to reach 0 or 1.

%H Seiichi Manyama, <a href="/A031355/b031355.txt">Table of n, a(n) for n = 1..10000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/MultiplicativePersistence.html">Multiplicative Persistence</a>

%o (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

%K nonn,base

%O 1,2

%A _Eric W. Weisstein_

%E Offset 1 from _Seiichi Manyama_, Jan 13 2020

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Last modified June 20 12:38 EDT 2024. Contains 373527 sequences. (Running on oeis4.)