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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A247543 Numbers k such that d(r,k) = 0 and d(s,k) = 1, where d(x,k) = k-th binary digit of x, r = {e}, s = {1/e}, and { } = fractional part. 4
2, 5, 13, 14, 21, 25, 28, 29, 35, 36, 40, 44, 49, 50, 52, 54, 56, 60, 73, 77, 78, 79, 81, 86, 87, 88, 95, 117, 125, 129, 132, 133, 140, 141, 152, 153, 155, 161, 166, 168, 170, 173, 179, 182, 184, 187, 192, 196, 203, 211, 217, 218, 220, 225, 227, 230, 238 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Every positive integer lies in exactly one of these: A247542, A247543, A247544, A247545.

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..1000

EXAMPLE

{e/1} has binary digits 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, ...

{1/e} has binary digits 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, ...

so that a(1) = 2 and a(2) = 5.

MATHEMATICA

z = 400; r = FractionalPart[E]; s = FractionalPart[1/E];

u = Flatten[{ConstantArray[0, -#[[2]]], #[[1]]}] &[RealDigits[r, 2, z]]

v = Flatten[{ConstantArray[0, -#[[2]]], #[[1]]}] &[RealDigits[s, 2, z]]

t1 = Table[If[u[[n]] == 0 && v[[n]] == 0, 1, 0], {n, 1, z}];

t2 = Table[If[u[[n]] == 0 && v[[n]] == 1, 1, 0], {n, 1, z}];

t3 = Table[If[u[[n]] == 1 && v[[n]] == 0, 1, 0], {n, 1, z}];

t4 = Table[If[u[[n]] == 1 && v[[n]] == 1, 1, 0], {n, 1, z}];

Flatten[Position[t1, 1]]  (* A247542 *)

Flatten[Position[t2, 1]]  (* A247543 *)

Flatten[Position[t3, 1]]  (* A247544 *)

Flatten[Position[t4, 1]]  (* A247545 *)

CROSSREFS

Cf. A247542, A247544, A247545.

Sequence in context: A111296 A089728 A127987 * A220268 A049476 A216889

Adjacent sequences:  A247540 A247541 A247542 * A247544 A247545 A247546

KEYWORD

nonn,easy,base

AUTHOR

Clark Kimberling, Sep 21 2014

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 January 23 14:31 EST 2022. Contains 350512 sequences. (Running on oeis4.)