A256078 Write n in binary, exchange digits '0' <-> '1'.

1, 0, 1, 0, 11, 10, 1, 0, 111, 110, 101, 100, 11, 10, 1, 0, 1111, 1110, 1101, 1100, 1011, 1010, 1001, 1000, 111, 110, 101, 100, 11, 10, 1, 0, 11111, 11110, 11101, 11100, 11011, 11010, 11001, 11000, 10111, 10110, 10101, 10100, 10011, 10010, 10001, 10000

Offset: 0

Author

M. F. Hasler, Mar 22 2015

Keywords

• nonn
• base
• easy

Comments

Binary representation of A035327.

A base-2 analog of A048379.

Links

• Robert Israel, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A035327, A048379.

Programs

Maple

f:= proc(n) local L,i;
  L:= convert(n,base,2);
  add((1-L[i])*10^(i-1),i=1..nops(L))
end proc:
map(f, [$0..100]); # Robert Israel, Sep 17 2024

Mathematica

Table[FromDigits[IntegerDigits[n, 2] /. {0 -> 1, 1 -> 0}], {n, 0, 47}] (* or *)
Table[FromDigits@ IntegerDigits[BitXor[n, 2^IntegerPart[Log[2, n] + 1] - 1], 2], {n, 0, 47}] (* Michael De Vlieger, Mar 22 2015, the latter based on Alonso del Arte at A035327 *)

PARI

A256078(n)=!n+eval(Strchr(apply(d->49-d,binary(n))))

Python

def a(n): return int(bin(1 if n==0 else n^((1 << n.bit_length())-1))[2:])
print([a(n) for n in range(48)]) # Michael S. Branicky, Dec 21 2022