OFFSET
0,3
LINKS
Rémy Sigrist, Table of n, a(n) for n = 0..8192
FORMULA
Empirically, if 2^k <= n < 2^(k+1) then a(n) + a(A054429(n)) only depends on k.
EXAMPLE
The first terms, alongside the corresponding k's, are:
n a(n) k's
-- ---- -------------------
0 0 None
1 0 None
2 2 0, 1
3 2 0, 1
4 2 1, 3
5 2 0, 2
6 4 1, 3, 4, 5
7 4 0, 2, 4, 5
8 2 3, 5
9 2 2, 4
10 4 1, 7, 8, 9
11 4 0, 6, 8, 9
12 4 1, 7, 9, 11
13 4 0, 6, 8, 10
14 6 3, 5, 9, 11, 12, 13
15 6 2, 4, 8, 10, 12, 13
PROG
(PARI) a(n) = sum(k = 0, n, isprime(bitxor(n, k)))
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Rémy Sigrist, Aug 17 2024
STATUS
approved