login
a(n) = 2*A156552(n) OR A323243(n), where OR is bitwise-OR, A003986.
5

%I #6 Mar 18 2019 21:49:13

%S 0,3,7,6,15,14,31,14,12,31,63,30,127,50,22,30,255,30,511,54,39,114,

%T 1023,62,28,214,28,118,2047,42,4095,62,118,434,42,62,8191,770,148,126,

%U 16383,110,32767,198,44,1826,65535,126,60,63,508,390,131071,62,91,206,532,3350,262143,126,524287,6834,124,126,254,234,1048575,822

%N a(n) = 2*A156552(n) OR A323243(n), where OR is bitwise-OR, A003986.

%H Antti Karttunen, <a href="/A324819/b324819.txt">Table of n, a(n) for n = 1..10000</a> (based on Hans Havermann's factorization of A156552)

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

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

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

%F a(A000040(n)) = A000225(1+n).

%o (PARI)

%o 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 A324819(n) = bitor(2*A156552(n),A323243(n)); \\ Needs code also from A323243.

%Y Cf. A003986, A156552, A323243, A324815, A324821.

%K nonn

%O 1,2

%A _Antti Karttunen_, Mar 18 2019