login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

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 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A143071 A positive integer n is included if the number of 1's in the binary representation of n is a power of 2 (including being possibly 1). 4
1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 17, 18, 20, 23, 24, 27, 29, 30, 32, 33, 34, 36, 39, 40, 43, 45, 46, 48, 51, 53, 54, 57, 58, 60, 64, 65, 66, 68, 71, 72, 75, 77, 78, 80, 83, 85, 86, 89, 90, 92, 96, 99, 101, 102, 105, 106, 108, 113, 114, 116, 120, 128, 129, 130, 132, 135 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

A209229(A000120(a(n))) = 1. - Reinhard Zumkeller, Sep 14 2014

EXAMPLE

34 in binary is 100010. This has 2 ones. And since 2 is a power of 2, 34 is included in the sequence.

MAPLE

a:=proc(n) local nn, n1: nn:=convert(n, base, 2): n1:=add(nn[j], j=1..nops(nn)): if 0 < n1 and type(log[2](n1), integer)=true then n else end if end proc: seq(a(n), n=1..140); # Emeric Deutsch, Aug 13 2008

MATHEMATICA

Select[Range[150], IntegerQ[Log2[DigitCount[#, 2, 1]]]&] (* Harvey P. Dale, Sep 26 2020 *)

PROG

(Haskell)

a143071 n = a143071_list !! (n-1)

a143071_list = filter ((== 1) . a209229 . a000120) [1..]

-- Reinhard Zumkeller, Sep 14 2014

CROSSREFS

Cf. A000120, A143070, A143072, A209229.

For complement see A271499.

Sequence in context: A082415 A005236 A051250 * A305759 A143513 A062849

Adjacent sequences:  A143068 A143069 A143070 * A143072 A143073 A143074

KEYWORD

base,nonn

AUTHOR

Leroy Quet, Jul 22 2008

EXTENSIONS

More terms from Emeric Deutsch, Aug 13 2008

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 5 12:24 EST 2021. Contains 349557 sequences. (Running on oeis4.)