A213526 a(n) = 3*n AND n, where AND is the bitwise AND operator.

0, 1, 2, 1, 4, 5, 2, 5, 8, 9, 10, 1, 4, 5, 10, 13, 16, 17, 18, 17, 20, 21, 2, 5, 8, 9, 10, 17, 20, 21, 26, 29, 32, 33, 34, 33, 36, 37, 34, 37, 40, 41, 42, 1, 4, 5, 10, 13, 16, 17, 18, 17, 20, 21, 34, 37, 40, 41, 42, 49, 52, 53, 58, 61, 64, 65, 66, 65, 68

Offset

0,3

Comments

Indices of 1's: A007583(n),

indices of 2's: A047849(n+1),

indices of 4's: A039301(n+2),

indices of 5's: A153643(n+3),

indices of 8's: A155701(n+2),

indices of 9's: A155701(n+2)+1 = A163868(n+2),

indices of 10's: A153643(n+4)+3^((n+1) mod 2),

indices of 13's: A039301(n+3)+3,

indices of 16's: A039301(n+3)+4,

indices of 17's: 17, 19, 27, 49, 51, 91, 177, 179, 347, 689, 691, 1371, 2737, 2739, 5467, 10929, 10931, 21851, 43697, 43699, 87387, 174769, 174771, 349531, 699057, 699059, 1398107, 2796209, 2796211, 5592411, 11184817, 11184819, 22369627, 44739249, 44739251, 89478491, ...

indices of 18's: A039301(n+3)+6,

n's such that a(n)<3: A005578, except the first term.

Links

Alois P. Heinz, Table of n, a(n) for n = 0..10000

Maple

a:= proc(n) local i, k, m, r;
      k, m, r:= n, 3*n, 0;
      for i from 0 while (m>0 or k>0) do
        r:= r +2^i* irem(m, 2, 'm') *irem(k, 2, 'k')
      od; r
    end:
seq(a(n), n=0..100);  # Alois P. Heinz, Jun 22 2012

Mathematica

Table[BitAnd[n, 3*n], {n, 0, 68}] (* Arkadiusz Wesolowski, Jun 23 2012 *)

Prog

(Python)
for n in range(99):
    print(3*n & n, end=', ')
(PARI) a(n)=bitand(n, 3*n) \\ Charles R Greathouse IV, Feb 05 2013

Crossrefs

Sequence in context: A038574 A212713 A072014 * A308364 A210707 A078606

Adjacent sequences: A213523 A213524 A213525 * A213527 A213528 A213529

Keyword

nonn,base,easy,look

Author

Alex Ratushnyak, Jun 13 2012

Status

approved