cp's OEIS Frontend

A324727 Odd numbers such that 2n is equal to A318466(n), bitor(2*n,sigma(n)), where bitor is A003986.

%I A324727 #20 Mar 11 2024 09:17:08
%S A324727 3,7,15,21,31,55,57,63,93,105,111,127,171,189,201,213,215,217,231,237,
%T A324727 249,253,255,315,351,357,363,369,381,393,447,465,469,473,483,489,497,
%U A324727 501,511,651,705,747,759,789,813,831,833,879,889,895,917,959,987,989,1001,1015,1023,1155,1365,1377,1407,1467,1491,1503,1505,1515,1533,1595
%N A324727 Odd numbers such that 2n is equal to A318466(n), bitor(2*n,sigma(n)), where bitor is A003986.
%H A324727 Antti Karttunen, <a href="/A324727/b324727.txt">Table of n, a(n) for n = 1..20000</a>
%H A324727 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H A324727 <a href="/index/O#opnseqs">Index entries for sequences where any odd perfect numbers must occur</a>
%H A324727 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%t A324727 Select[Range[1, 2000, 2], 2*# == BitOr[2*#, DivisorSigma[1, #]] &] (* _Paolo Xausa_, Mar 11 2024 *)
%o A324727 (PARI) for(n=1,oo,if((n%2)&&((2*n)==bitor(2*n,sigma(n))),print1(n,", ")));
%Y A324727 Odd terms of A324726.
%Y A324727 Cf. A000203, A003986, A318466, A324647, A324718, A324719.
%K A324727 nonn,look
%O A324727 1,1
%A A324727 _Antti Karttunen_, Mar 15 2019