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A276555 Number of steps to reach 1 when starting from n and iterating the map x -> x - A061395(x). 1

%I #12 May 26 2017 21:15:28

%S 0,1,1,2,2,3,2,3,3,3,4,4,3,4,5,6,4,7,5,5,5,5,5,6,6,6,7,7,6,8,6,7,8,8,

%T 7,9,7,9,9,8,8,10,7,10,11,8,8,9,12,9,11,9,8,10,10,10,13,10,11,14,8,12,

%U 12,13,12,9,10,9,15,10,12,11,10,13,12,10,12,12

%N Number of steps to reach 1 when starting from n and iterating the map x -> x - A061395(x).

%C This sequence tends to infinity as n tends to infinity.

%C This sequence is similar to A282630; here we consider the greatest prime factor of a number, there we consider its least prime factor.

%H Rémy Sigrist, <a href="/A276555/b276555.txt">Table of n, a(n) for n = 1..10000</a>

%H Rémy Sigrist, <a href="/A276555/a276555.png">Illustration of the first terms</a>

%H Rémy Sigrist, <a href="/A276555/a276555_1.png">Scatterplot of the ordinal transform of the first million terms</a>

%o (PARI) a = vector(100); for (n=1, #a, if (n>1, my (f=factor(n)); a[n] = 1 + a[n - primepi(f[#f~, 1])]); print1 (a[n] ", "))

%Y Cf. A061395, A282630.

%K nonn

%O 1,4

%A _Rémy Sigrist_, Apr 10 2017

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Last modified March 29 09:59 EDT 2024. Contains 371268 sequences. (Running on oeis4.)