OFFSET
0,5
COMMENTS
Partial sums at positions 2^m-1 = m*2^(m-2) for m>=2.
EXAMPLE
Partial sums at 2^m-1 are:
at 2^2-1 (m=2): 0+1+1+0 = 2 = 2*2^(2-2),
at 2^3-1 (m=3): 0+1+1+0+2+1+1+0 = 6 = 3*2^(3-2),
at 2^4-1 (m=4): 0+1+1+0+2+1+1+0+2+1+3+0+2+1+1+0 = 16 = 4*2^(4-2).
PROG
(PARI) {a(n)=sum(k=0, (n-1)\2, if(bitxor(n-k, k)==2^valuation(bitxor(n-k, k), 2), 1, 0))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Dec 23 2004
STATUS
approved