A048717 Binary expansion matches ((0)*00(1*)11)*(0*).

0, 3, 6, 7, 12, 14, 15, 24, 28, 30, 31, 48, 51, 56, 60, 62, 63, 96, 99, 102, 103, 112, 115, 120, 124, 126, 127, 192, 195, 198, 199, 204, 206, 207, 224, 227, 230, 231, 240, 243, 248, 252, 254, 255, 384, 387, 390, 391

Offset: 0

Author

Antti Karttunen, Mar 30 1999

Keywords

• nonn
• base
• easy

Comments

In binary expansion, 1-bits occur only in groups of two or more, separated from other such groups by at least two 0-bits.

Integers that satisfy A048727(n) = 3*n.

Links

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

Crossrefs

Row 3 of A115872. Superset of A048719. Cf. A048733.

Programs

Mathematica

filterQ[n_] := !MatchQ[IntegerDigits[n, 2], {1}|{1, 0, _}|{_, 0, 1}|{_, 1, 0, 1, _}|{_, 0, 1, 0, _}];
Select[Range[0, 400], filterQ] (* Jean-François Alcover, Dec 31 2020 *)