cp's OEIS Frontend

A364495 Odd numbers k such that k divides A163511(k).

%I A364495 #15 Sep 02 2023 11:24:42
%S A364495 1,3,9,105,429,1365,1617,3887,4235,10829,14025,17745,21125,22627,
%T A364495 38025,54587,70805,100555,115159,147875,168751,169065,175769,181447,
%U A364495 181545,291525,297297,303875,338675,350987,501787,513825,518035,549081,560947,566865,594473,624169,676039,735875,745147,831875,869193,957125
%N A364495 Odd numbers k such that k divides A163511(k).
%H A364495 Antti Karttunen, <a href="/A364495/b364495.txt">Table of n, a(n) for n = 1..801</a>
%e A364495 For n = 513825 = 3 * 5^2 * 13 * 17 * 31, A163511(n) = 13873275 = 3^4 * 5^2 * 13 * 17 * 31, so A163511(n)/n = 27 (which is an integer), and therefore 513825 is included in this sequence.
%o A364495 (PARI)
%o A364495 A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
%o A364495 A054429(n) = ((3<<#binary(n\2))-n-1);
%o A364495 A163511(n) = if(!n,1,A005940(1+A054429(n)))
%o A364495 A163511(n) = if(!n,1,my(p=2, t=1); while(n>1, if(!(n%2), (t*=p), p=nextprime(1+p)); n >>= 1); (t*p));
%o A364495 isA364495(n) = ((n%2)&&!(A163511(n)%n));
%Y A364495 Odd terms in A364494.
%Y A364495 After 1, sequence A243071(A364965(n)), for n>=1, sorted into ascending order.
%Y A364495 Cf. A163511.
%Y A364495 Cf. also A364296, A364498, A364545, A364963.
%K A364495 nonn
%O A364495 1,2
%A A364495 _Antti Karttunen_, Jul 27 2023