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a(n) = n mod A181819(n), where A181819(n) is the prime shadow of n.
6

%I #6 May 30 2024 10:09:52

%S 0,0,1,1,1,2,1,3,0,2,1,0,1,2,3,2,1,0,1,2,1,2,1,4,1,2,2,4,1,6,1,10,1,2,

%T 3,0,1,2,3,0,1,2,1,2,3,2,1,6,1,2,3,4,1,4,3,6,1,2,1,0,1,2,3,12,1,2,1,2,

%U 1,6,1,12,1,2,3,4,1,6,1,10,4,2,1,0,1,2,3,8,1,6,3,2,1,2,3,8,1,2,3,1,1,6,1,4,1

%N a(n) = n mod A181819(n), where A181819(n) is the prime shadow of n.

%H Antti Karttunen, <a href="/A373247/b373247.txt">Table of n, a(n) for n = 1..65537</a>

%o (PARI)

%o A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2])));

%o A373247(n) = (n%A181819(n));

%Y Cf. A181819, A373246.

%Y Cf. A325755 (positions of 0's), A353566 (their characteristic function).

%K nonn

%O 1,6

%A _Antti Karttunen_, May 29 2024