cp's OEIS Frontend

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.

%I A325567 #8 May 11 2019 02:23:52
%S A325567 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 A325567 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 A325567 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 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.
%H A325567 Antti Karttunen, <a href="/A325567/b325567.txt">Table of n, a(n) for n = 1..16383</a>
%H A325567 Antti Karttunen, <a href="/A325567/a325567.txt">Data supplement: n, a(n) computed for n = 1..65537</a>
%o A325567 (PARI)
%o A325567 A048720(b,c) = fromdigits(Vec(Pol(binary(b))*Pol(binary(c)))%2, 2);
%o A325567 A065621(n) = bitxor(n-1,n+n-1);
%o A325567 A325567(n) = if(1==n,n,fordiv(n,d,if((d>1)&&A048720(A065621(n/d),d)==n,return(n/d))));
%Y A325567 Cf. A032742, A048720, A065621, A115872, A325565, A325566, A325568.
%K A325567 nonn
%O A325567 1,4
%A A325567 _Antti Karttunen_, May 09 2019