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%I #7 Sep 01 2023 15:23:57
%S 3,27,315,3003,42757,72765,195195,799425,13873275,18131225
%N Odd numbers k such that k is a multiple of A243071(k).
%o (PARI)
%o A243071(n) = if(n<=2, n-1, my(f=factor(n), p, p2=1, res=0); for(i=1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p*p2*(2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); ((3<<#binary(res\2))-res-1)); \\ (Combining programs given in A156552 and A054429)
%o isA364965(n) = ((n>1)&&(n%2)&&!(n%A243071(n)));
%Y Odd terms in A364964.
%Y Sequence A163511(A364495(n)), for n>1, sorted into ascending order.
%Y Cf. A243071.
%Y Cf. also A364498, A364551.
%K nonn,more
%O 1,1
%A _Antti Karttunen_, Sep 01 2023