cp's OEIS Frontend

A324722 Numbers k such that A324658(A156552(k)) is zero.

%I A324722 #18 Jul 30 2021 08:50:23
%S A324722 9,21,25,35,49,55,77,95,121,125,133,143,169,185,203,209,221,265,289,
%T A324722 299,301,319,323,343,361,371,377,413,427,437,445,451,473,481,493,497,
%U A324722 511,527,529,531,539,553,559,583,589,605,611,623,629,667,679,689,703,707,737,763,767,779,791,793,799,805,817,841,845,847,851,869,871,899,901
%N A324722 Numbers k such that A324658(A156552(k)) is zero.
%C A324722 First even term is A005940(1+A324647(1)) = A005940(1+1116225) = 1912898. - Typo corrected by _Antti Karttunen_, Jul 21 2021
%H A324722 Antti Karttunen, <a href="/A324722/b324722.txt">Table of n, a(n) for n = 1..694</a> (based on Hans Havermann's factorization of A156552)
%H A324722 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H A324722 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H A324722 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%o A324722 (PARI)
%o A324722 isA324652(n) = ((2*n)==bitand(2*n, sigma(n)));
%o A324722 isA324722(n) = if(n>1,isA324652(A156552(n)));
%o A324722 k=0; n=0; while(k<105, n++; if(isA324722(n), k++; print1(n,", ")));
%Y A324722 Cf. A005940, A156552, A324647, A324652, A324658, A324723.
%Y A324722 Positions of zeros in A324716.
%K A324722 nonn
%O A324722 1,1
%A A324722 _Antti Karttunen_, Mar 15 2019