|
|
A181740
|
|
Number of sequences of length n over {1, -1} with Erdős discrepancy <= 2.
|
|
2
|
|
|
1, 2, 4, 6, 12, 18, 28, 44, 88, 100, 152, 240, 370, 556, 882, 750, 1500, 2250, 2784, 4284, 6438, 6062, 9526, 14856, 22944, 26164, 39528, 35122, 54800, 80940, 81326, 122422, 244844, 234934, 356154, 309068, 388042, 589796, 900000, 813466, 1212450, 1837030
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
The Erdős discrepancy of sequence s is defined to be the maximum of the absolute value of s(d) + s(2d) + ... + s(kd) over all k, d such that kd <= n.
|
|
LINKS
|
|
|
EXAMPLE
|
For n = 3 the only sequences omitted are 1 1 1 and -1 -1 -1, so a(3) = 6.
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|