A161602 Positive integers k that are greater than the value of the reversal of k's binary representation.

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

Offset: 1

Author

Leroy Quet, Jun 14 2009

Keywords

• base
• nonn

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.

Examples

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

Links

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

Crossrefs

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

Cf. A071590 (using decimal reversal).

Programs

Mathematica

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

PARI

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

Python

from itertools import count, islice
def A161602_gen(startvalue=1): # generator of terms >= startvalue
    return filter(lambda n:n>int(bin(n)[-1:1:-1],2),count(max(startvalue,1)))
A161602_list = list(islice(A161602_gen(),20)) # Chai Wah Wu, Jan 19 2023

Extensions

More terms from Max Alekseyev, Sep 11 2009