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A181740 Number of sequences of length n over {1, -1} with Erdos discrepancy <= 2. This sequence may be finite. 0
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 Erdos discrepancy is defined to be the maximum of the absolute value of a(d)+a(2d) + ... + a(kd) over all k, d such that kd <= n.

LINKS

Table of n, a(n) for n=0..41.

Michael Nielsen, Erdos discrepancy problem

EXAMPLE

For n = 3 the only sequences omitted are 1 1 1 and -1 -1 -1, so a(3) = 6.

CROSSREFS

Sequence in context: A051683 A215821 A192096 * A192224 A167777 A007436

Adjacent sequences:  A181737 A181738 A181739 * A181741 A181742 A181743

KEYWORD

nonn,changed

AUTHOR

Jeffrey Shallit, Nov 08 2010

EXTENSIONS

a(30) through a(41) from Allan C. Wechsler, Sep 19 2012.

STATUS

approved

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Last modified June 19 23:42 EDT 2013. Contains 226416 sequences.