A048719 Binary expansion matches ((0)*0011)*(0*).

0, 3, 6, 12, 24, 48, 51, 96, 99, 102, 192, 195, 198, 204, 384, 387, 390, 396, 408, 768, 771, 774, 780, 792, 816, 819, 1536, 1539, 1542, 1548, 1560, 1584, 1587, 1632, 1635, 1638, 3072, 3075, 3078, 3084, 3096

Offset: 0

Author

Antti Karttunen, Mar 30 1999

Keywords

• nonn
• base
• easy

Comments

1-bits occur only in pairs, separated from other such pairs by at least two 0-bits.

All terms satisfy both A048727(n) = 3*n and A048725(n) = 5*n.

Links

• Index entries for sequences defined by congruent products between domains N and GF(2)[X]

Crossrefs

Intersection of A048716 and A048717.

Programs

Mathematica

filterQ[n_] := With[{bb = IntegerDigits[n, 2]}, !MatchQ[bb, {1}|{1, 0, _}|{_, 0, 1}|{_, 0, 1, 0, _}|{_, 1, 1, 1, _}|{_, 1, 0, 1, _}]];
Select[Range[0, 3096], filterQ] (* Jean-François Alcover, Dec 31 2020 *)

PARI

is(n)=n%3==0 && !bitand(n/3, 14*n/3) \\ Charles R Greathouse IV, Oct 03 2016

Formula

a(n) = 3*A048718(n).