The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A175262 Those positive integers that when written in binary contain an odd number of digits, the middle digit being a 1. 1
 1, 6, 7, 20, 21, 22, 23, 28, 29, 30, 31, 72, 73, 74, 75, 76, 77, 78, 79, 88, 89, 90, 91, 92, 93, 94, 95, 104, 105, 106, 107, 108, 109, 110, 111, 120, 121, 122, 123, 124, 125, 126, 127, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS MAPLE isA175262 := proc(n) local dgs ; dgs := convert(n, base, 2) ; if type(nops(dgs), 'odd') then return ( op( (nops(dgs)+1)/2 , dgs) = 1 ) ; else false ; end if; end proc: for n from 1 to 400 do if isA175262(n) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, Mar 29 2010 MATHEMATICA ondQ[n_]:=Module[{id=IntegerDigits[n, 2], len}, len=Length[id]; OddQ[len] && id[[(len+1)/2]]==1]; Select[Range[300], ondQ] (* Harvey P. Dale, Apr 01 2018 *) CROSSREFS Cf. A175263. Sequence in context: A287760 A305675 A210605 * A345911 A081348 A002361 Adjacent sequences: A175259 A175260 A175261 * A175263 A175264 A175265 KEYWORD base,nonn AUTHOR Leroy Quet, Mar 16 2010 EXTENSIONS More terms from R. J. Mathar, Mar 29 2010 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 29 09:49 EST 2022. Contains 358423 sequences. (Running on oeis4.)