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A325567 a(1) = 1; for n > 1, a(n) is the largest proper divisor d of n such that A048720(A065621(d),n/d) is equal to n. 9

%I

%S 1,1,1,2,1,2,1,4,3,2,1,4,1,2,1,8,1,6,1,4,3,2,1,8,1,2,1,4,1,2,1,16,11,

%T 2,5,12,1,2,1,8,1,6,1,4,3,2,1,16,7,2,1,4,1,2,1,8,1,2,1,4,1,2,1,32,13,

%U 22,1,4,1,10,1,24,1,2,5,4,1,2,1,16,1,2,1,12,1,2,1,8,1,6,1,4,3,2,1,32,1,14,1,4,1,2,1,8,7

%N a(1) = 1; for n > 1, a(n) is the largest proper divisor d of n such that A048720(A065621(d),n/d) is equal to n.

%H Antti Karttunen, <a href="/A325567/b325567.txt">Table of n, a(n) for n = 1..16383</a>

%H Antti Karttunen, <a href="/A325567/a325567.txt">Data supplement: n, a(n) computed for n = 1..65537</a>

%o (PARI)

%o A048720(b,c) = fromdigits(Vec(Pol(binary(b))*Pol(binary(c)))%2, 2);

%o A065621(n) = bitxor(n-1,n+n-1);

%o A325567(n) = if(1==n,n,fordiv(n,d,if((d>1)&&A048720(A065621(n/d),d)==n,return(n/d))));

%Y Cf. A032742, A048720, A065621, A115872, A325565, A325566, A325568.

%K nonn

%O 1,4

%A _Antti Karttunen_, May 09 2019

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Last modified July 27 02:39 EDT 2021. Contains 346302 sequences. (Running on oeis4.)