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A333523 Number of iterations of Reverse And Add needed to reach a number divisible by n (or 0 if such a number is never reached). 1

%I #16 Apr 11 2020 08:25:10

%S 1,1,1,1,1,1,1,1,1,61,1,3,8,34,22,8,17,2,8,119,14,1,17,7,110,7,12,33,

%T 34,158,28,12,1,60,11,12,50,79,7,129,64,13,42,1,4,89,131,8,14,81,30,

%U 19,125,12,1,88,13,33,67,232,26,27,24,123,59,1,24,59,36,206,148,12,217,90,97

%N Number of iterations of Reverse And Add needed to reach a number divisible by n (or 0 if such a number is never reached).

%C If n is a palindrome > 0, a(n) = 1. See A002113.

%C a(n) > 0 for n < 10000.

%H Daniel Starodubtsev, <a href="/A333523/b333523.txt">Table of n, a(n) for n = 1..10000</a>

%e a(12) = 3, because 12 takes 3 iterations (12 -> 33 -> 66 -> 132) to become 132, which is divisible by 12.

%o (PARI) radd(n) = fromdigits(Vecrev(digits(n)))+n; \\ A056964

%o a(n) = {my(i=1, k=n, x); while((x=radd(n)) % k, i++; n=x); i;} \\ _Michel Marcus_, Apr 11 2020

%Y Cf. A002113, A016016, A056964.

%K nonn,base

%O 1,10

%A _Daniel Starodubtsev_, Mar 26 2020

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Last modified September 10 06:17 EDT 2024. Contains 375773 sequences. (Running on oeis4.)