A324659 - OEIS

%I #12 Mar 12 2024 05:01:33

%S 0,0,2,0,1,6,4,0,0,8,2,12,5,12,12,0,1,18,2,20,16,18,4,24,9,16,16,28,

%T 13,4,16,0,0,2,0,36,1,6,4,40,1,32,2,40,37,36,8,48,16,34,32,48,17,52,

%U 36,56,40,40,26,20,29,48,52,0,0,64,2,4,0,64,4,64,1,8,10,68,0,68,8,80,16,18,2,80,20,66,20,88,9,80

%N a(n) = (1/2)*A318468(n), where A318468(n) is bitwise-AND of 2*n and sigma(n).

%H Antti Karttunen, <a href="/A324659/b324659.txt">Table of n, a(n) for n = 1..16384</a>

%H <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>

%F a(n) = A318468(n)/2.

%F a(n) = n - A324658(n).

%t Array[BitAnd[2*#, DivisorSigma[1, #]]/2 &, 100] (* _Paolo Xausa_, Mar 11 2024 *)

%o (PARI) A324659(n) = (bitand(2*n,sigma(n))/2);

%Y Cf. A000203, A004198, A318458, A318468, A324648, A324658.

%Y Cf. A324652 (fixed points).

%K nonn,look

%O 1,3

%A _Antti Karttunen_, Mar 14 2019