|
| |
|
|
A143241
|
|
Expansion of Product_{k>0} (1 - x^k) / (1 - x^(6*k - 2)).
|
|
0
| |
|
|
1, -1, -1, 0, 1, 0, -1, 1, 1, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 1, 0, -1, 0, 0, 0, 1, 1, -1, 0, 1, 0, 0, 0, -1, -1, 1, 1, 0, 0, -1, 0, 1, 0, -1, -1, 0, 0, 1, 0, -1, 0, 0, 0, 1, 0, -1, 0, 1, 0, 0, 1, -1, -1, 1, 0, 1, 0, -1, -1, 1, 1, -1, 1, 0, -1, 1, 1, 0, -1, -1, -1, 1, 1, -1, -1, 0, 0, 1, 1, -1, -1, 0, 0, 1, 1, -1, -1, 0, 0, 1, 1, -1, -2, 0
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,104
|
|
|
COMMENTS
| |a(n)|<2 if n<103, |a(n)|<3 if n<161.
|
|
|
FORMULA
| Euler transform of period 6 sequence [ -1, -1, -1, 0, -1, -1, ...].
G.f.: Product_{k>0} (1 - x^k) / (1 - x^(6*k - 2)).
|
|
|
EXAMPLE
| 1 - q - q^2 + q^4 - q^6 + q^7 + q^8 - q^12 - q^18 + q^20 - q^22 + ...
|
|
|
PROG
| (PARI) {a(n) = if( n<0, 0, polcoeff( prod(k=1, n, (1 - x^k)^([1, 1, 1, 1, 0, 1][k%6 + 1]), 1 + x * O(x^n)), n))}
|
|
|
CROSSREFS
| Sequence in context: A160338 A174845 A037281 * A118626 A062892 A118553
Adjacent sequences: A143238 A143239 A143240 * A143242 A143243 A143244
|
|
|
KEYWORD
| sign
|
|
|
AUTHOR
| Michael Somos, Aug 01 2008
|
| |
|
|
