A031449 Numbers whose base-2 representation has two fewer 0's than 1's.

3, 11, 13, 14, 39, 43, 45, 46, 51, 53, 54, 57, 58, 60, 143, 151, 155, 157, 158, 167, 171, 173, 174, 179, 181, 182, 185, 186, 188, 199, 203, 205, 206, 211, 213, 214, 217, 218, 220, 227, 229, 230, 233, 234, 236, 241, 242, 244, 248, 543, 559, 567, 571, 573, 574

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Artūras Dubickas, On a sequence of rational numbers with unusual divisibility by a power of 2, Miskolc Math. Notes (2024) Vol. 25, No. 1, 203-208. Mentions this sequence.

Example

13 in binary is 1101, which has three 1's but only one 0, hence 13 is in the sequence.
14 in binary is 1110, which has three 1's but only one 0, hence 14 is in the sequence.
15 in binary is 1111, which has four 1's but no significant 0's, hence 15 is not in the sequence.

Mathematica

Select[Range[700], DigitCount[#, 2, 0] == DigitCount[#, 2, 1] - 2 &] (* Vincenzo Librandi, Aug 24 2013 *)

Crossrefs

Cf. A007088, A023416, A080791 (these two sequences are identical except for a(0), which is irrelevant for this sequence because 0 has no 1's).

Sequence in context: A254220 A119231 A177335 * A305859 A090260 A179522

Adjacent sequences: A031446 A031447 A031448 * A031450 A031451 A031452

Keyword

nonn,easy,base

Author

Clark Kimberling

Extensions

More terms from Vincenzo Librandi, Aug 24 2013

Status

approved