A334076 a(n) = bitwise NOR of n and 2n.

0, 0, 1, 0, 3, 0, 1, 0, 7, 4, 1, 0, 3, 0, 1, 0, 15, 12, 9, 8, 3, 0, 1, 0, 7, 4, 1, 0, 3, 0, 1, 0, 31, 28, 25, 24, 19, 16, 17, 16, 7, 4, 1, 0, 3, 0, 1, 0, 15, 12, 9, 8, 3, 0, 1, 0, 7, 4, 1, 0, 3, 0, 1, 0, 63, 60, 57, 56, 51, 48, 49, 48, 39, 36, 33, 32, 35, 32, 33

Offset: 0

Author

Alois P. Heinz, Apr 13 2020

Keywords

• nonn
• look
• base

Comments

Exactly all bits that are 0 in both parameters (but not a leading 0 of both) are set to 1 in the output of bitwise NOR.

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..32767
• Wikipedia, Bitwise operation

Crossrefs

Cf. A000079, A048724, A125835, A141032, A163617, A213370, A247648.

Programs

Maple

a:= n-> Bits[Nor](n, 2*n):
seq(a(n), n=0..127);

PARI

a(n) = my(x=bitor(n, 2*n)); bitneg(x, #binary(x)); \\ Michel Marcus, Apr 14 2020

Python

def A334076(n):
    m = n|(2*n)
    return 0 if n == 0 else 2**(len(bin(m))-2)-1-m # Chai Wah Wu, Apr 14 2020

Formula

a(n) = 0 <=> n in { A247648 } union { 0 }.

a(n) = n-1 <=> n in { A000079 }.

a(n) = n/2 <=> n in { A125835 }.

a(n) = n*3/4 <=> n in { A141032 }.