OFFSET
0,13
COMMENTS
In other words, we keep even-indexed bits.
Every integer appears infinitely many times in the sequence.
LINKS
EXAMPLE
The first terms, in decimal and in binary, are:
n a(n) bin(n) bin(a(n))
-- ---- ------ ---------
0 0 0 0
1 0 1 0
2 0 10 0
3 1 11 1
4 0 100 0
5 0 101 0
6 1 110 1
7 1 111 1
8 0 1000 0
9 1 1001 1
10 0 1010 0
11 1 1011 1
12 2 1100 10
13 3 1101 11
14 2 1110 10
15 3 1111 11
16 0 10000 0
MATHEMATICA
A371459[n_] := FromDigits[IntegerDigits[n, 2][[2;; -1;; 2]], 2];
Array[A371459, 100, 0] (* Paolo Xausa, Mar 28 2024 *)
PROG
(PARI) a(n) = { my (b = binary(n)); fromdigits(vector(#b\2, k, b[2*k]), 2); }
(Python)
def A371459(n): return int(bin(n)[3::2], 2) if n>1 else 0 # Chai Wah Wu, Mar 27 2024
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Rémy Sigrist, Mar 24 2024
STATUS
approved