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A031449 Numbers whose base-2 representation has two fewer 0's than 1's. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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
KEYWORD
nonn,easy,base
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Aug 24 2013
STATUS
approved

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Last modified April 23 22:36 EDT 2024. Contains 371917 sequences. (Running on oeis4.)