

A342123


a(n) is the remainder when n is divided by its binary reverse.


3



0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 2, 0, 0, 0, 0, 0, 19, 0, 0, 9, 23, 0, 6, 4, 0, 0, 6, 0, 0, 0, 0, 0, 35, 0, 37, 13, 39, 0, 4, 0, 43, 5, 0, 17, 47, 0, 14, 12, 0, 8, 10, 0, 55, 0, 18, 12, 4, 0, 14, 0, 0, 0, 0, 0, 67, 0, 69, 21, 71, 0, 0, 33, 75, 1, 77, 21
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OFFSET

1,11


COMMENTS

The binary reverse of a number is given by A030101.
This sequence is the analog of A071955 for the binary base.


LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..8192
Index entries for sequences related to binary expansion of n


FORMULA

a(n) = n mod A030101(n).
a(n) <= n with equality iff n belongs to A161601.
a(n) = 0 iff n belongs to A057890.


EXAMPLE

For n = 43,
 the binary reverse of 43 ("101011" in binary) is 53 ("110101" in binary),
 so a(43) = 43 mod 53 = 43.


PROG

(PARI) a(n, base=2) = { my (r=fromdigits(Vecrev(digits(n, base)), base)); n%r }
(Python)
def A342123(n): return n % int(bin(n)[:1:1], 2) if n > 0 else 0 # Chai Wah Wu, Mar 01 2021


CROSSREFS

Cf. A030101, A057890, A071955, A161601, A342121, A342122.
Sequence in context: A138066 A173189 A115595 * A187553 A003621 A338827
Adjacent sequences: A342120 A342121 A342122 * A342124 A342125 A342127


KEYWORD

nonn,base,look,easy


AUTHOR

Rémy Sigrist, Feb 28 2021


STATUS

approved



