cp's OEIS Frontend

A324866 a(n) = A156552(n) OR A324865(n), where OR is bitwise-OR, A003986.

%I A324866 #9 Mar 18 2019 21:49:36
%S A324866 0,1,3,3,7,5,15,7,6,13,31,11,63,17,10,15,127,13,255,19,23,47,511,23,
%T A324866 28,83,14,47,1023,31,2047,31,54,175,22,31,4095,257,78,55,8191,37,
%U A324866 16383,67,30,799,32767,47,60,31,250,131,65535,29,55,71,270,1301,131071,43,262143,2735,54,63,126,95,524287,303,774,41,1048575,55
%N A324866 a(n) = A156552(n) OR A324865(n), where OR is bitwise-OR, A003986.
%H A324866 Antti Karttunen, <a href="/A324866/b324866.txt">Table of n, a(n) for n = 1..10000</a> (based on Hans Havermann's factorization of A156552)
%H A324866 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H A324866 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H A324866 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A324866 a(1) = 0; for n > 1, a(n) = A318456(A156552(n)).
%F A324866 a(n) = A156552(n) OR (A323243(n) - A156552(n)).
%o A324866 (PARI)
%o A324866 A156552(n) = {my(f = factor(n), 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]); res}; \\ From A156552
%o A324866 A318456(n) = bitor(n,sigma(n)-n);
%o A324866 A324866(n) = if(1==n,0,A318456(A156552(n)));
%o A324866 (PARI) A324866(n) = { my(k=A156552(n)); bitor(k,(A323243(n)-k)); }; \\ Needs also code from A323243.
%Y A324866 Cf. A001065, A003986, A156552, A318456, A323243, A324865, A324867, A324398, A324876.
%K A324866 nonn
%O A324866 1,3
%A A324866 _Antti Karttunen_, Mar 18 2019