A203622 a(n) = (a(n-1) OR a(n-2)) XOR n.

0, 1, 3, 0, 7, 2, 1, 4, 13, 4, 7, 12, 3, 2, 13, 0, 29, 12, 15, 28, 11, 10, 29, 8, 5, 20, 15, 4, 19, 10, 5, 16, 53, 20, 23, 52, 19, 18, 53, 16, 29, 52, 23, 28, 51, 18, 29, 48, 13, 12, 63, 12, 11, 58, 13, 8, 53, 4, 15, 52, 3, 10, 53, 0, 117, 52, 55, 116, 51, 50, 117

Offset

0,3

Comments

Indices of zeros: 2^(2x)-1, e.g. 0, 3, 15, 63, 255.

Links

Table of n, a(n) for n=0..70.

Formula

a(0)=0, a(1)=1, a(n) = (a(n-1) OR a(n-2)) XOR n, where OR is the bitwise inclusive-or operator, XOR is the bitwise exclusive-or operator.

Prog

(Python)
prpr = 0
prev = 1
for n in range(2, 77):
    current = (prev | prpr) ^ n
    print(prpr, end=', ')
    prpr = prev
    prev = current

Crossrefs

Cf. A182560.

Sequence in context: A021769 A200119 A291943 * A201571 A010600 A175918

Adjacent sequences: A203619 A203620 A203621 * A203623 A203624 A203625

Keyword

nonn,base,easy

Author

Alex Ratushnyak, May 06 2012

Status

approved