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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A161602 Positive integers k that are greater than the value of the reversal of k's binary representation. 4
2, 4, 6, 8, 10, 12, 13, 14, 16, 18, 20, 22, 24, 25, 26, 28, 29, 30, 32, 34, 36, 38, 40, 41, 42, 44, 46, 48, 49, 50, 52, 53, 54, 56, 57, 58, 59, 60, 61, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 81, 82, 84, 86, 88, 89, 90, 92, 94, 96, 97, 98, 100, 101, 102, 104, 105, 106, 108, 109 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

By "reversal" of k's binary representation, it is meant: write k in binary, reverse the order of its digits, and read the result as a binary value.

This sequence contains all the positive even integers.

LINKS

Jonathan Frech, Table of n, a(n) for n = 1..10000

EXAMPLE

29 in binary is 11101. Its digital reversal is 10111, which is 23 in decimal. Since 29 > 23, 29 is in this sequence.

MATHEMATICA

Select[Range[109], # > IntegerReverse[#, 2] &] (* Michael De Vlieger, Apr 07 2021 *)

PROG

(PARI) isok(k) = k > fromdigits(Vecrev(binary(k)), 2); \\ Michel Marcus, Apr 06 2021

CROSSREFS

Cf. A030101, A006995, A161601, A161603 (odd terms).

Cf. A071590 (using decimal reversal).

Sequence in context: A319807 A055954 A301454 * A285591 A327210 A274611

Adjacent sequences:  A161599 A161600 A161601 * A161603 A161604 A161605

KEYWORD

base,nonn,changed

AUTHOR

Leroy Quet, Jun 14 2009

EXTENSIONS

More terms from Max Alekseyev, Sep 11 2009

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 April 13 10:24 EDT 2021. Contains 342935 sequences. (Running on oeis4.)