login
A085425
Number of minus ones in the symmetric signed digit expansion of n with q=2 (i.e., the representation of n in the (-1,0,1)_2 number system).
1
0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 3, 2, 2, 2, 2, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 3, 3, 2, 2, 2, 3, 2, 2, 2, 2, 1
OFFSET
1,11
PROG
(PARI) ep(r, n)=local(t=n/2^(r+2)); floor(t+5/6)-floor(t+4/6)-floor(t+2/6)+floor(t+1/6);
a(n)=sum(r=0, log(3*n)\log(2)-1, (ep(r, n) == 1)) ;
CROSSREFS
Cf. A005578, A085423, A007302 (nonzeros), A057526 (0's), A085424 (1's).
Sequence in context: A122433 A056977 A309144 * A355685 A244250 A167230
KEYWORD
nonn,easy,base
AUTHOR
Ralf Stephan, Jun 30 2003
STATUS
approved