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

0, 1, 3, 3, 7, 5, 15, 7, 6, 13, 31, 11, 63, 17, 10, 15, 127, 13, 255, 19, 23, 47, 511, 23, 28, 83, 14, 47, 1023, 31, 2047, 31, 54, 175, 22, 31, 4095, 257, 78, 55, 8191, 37, 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

Offset: 1

Author

Antti Karttunen, Mar 18 2019

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000 (based on Hans Havermann's factorization of A156552)
• Index entries for sequences related to binary expansion of n
• Index entries for sequences computed from indices in prime factorization
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A001065, A003986, A156552, A318456, A323243, A324865, A324867, A324398, A324876.

Programs

PARI

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
A318456(n) = bitor(n,sigma(n)-n);
A324866(n) = if(1==n,0,A318456(A156552(n)));

PARI

A324866(n) = { my(k=A156552(n)); bitor(k,(A323243(n)-k)); }; \\ Needs also code from A323243.

Formula

a(1) = 0; for n > 1, a(n) = A318456(A156552(n)).

a(n) = A156552(n) OR (A323243(n) - A156552(n)).