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A284585
Expansion of Product_{k>=0} (1 - x^(6*k+1)) in powers of x.
4
1, -1, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, -1, 2, -1, 0, 0, 0, -1, 2, -1, 0, 0, 0, -1, 3, -2, 0, 0, 0, -1, 3, -3, 1, 0, 0, -1, 4, -4, 1, 0, 0, -1, 4, -5, 2, 0, 0, -1, 5, -7, 3, 0, 0, -1, 5, -8, 5, -1, 0, -1, 6, -10, 6, -1, 0, -1, 6, -12, 9, -2, 0, -1
OFFSET
0,21
LINKS
FORMULA
a(n) = -(1/n)*Sum_{k=1..n} A284098(k)*a(n-k), a(0) = 1.
a(n) = (-1)^n * A280456(n). - Robert Israel, Apr 09 2017
MAPLE
N:= 100: # to get a(0)..a(N)
V:= Vector(N+1):
V[1]:= 1:
for k from 0 to floor((N-1)/6) do
V[6*k+2..N+1]:= V[6*k+2..N+1]+V[1..N-6*k]
od:
seq((-1)^n*V[n+1], n=0..N); # Robert Israel, Apr 09 2017
MATHEMATICA
CoefficientList[Series[Product[1 - x^(6*k+1), {k, 0, 79}], {x, 0, 79}], x] (* Indranil Ghosh, Mar 29 2017 *)
CROSSREFS
Cf. Product_{k>=0} (1 - x^(6*k+m)): this sequence (m=1), A284586 (m=5).
Cf. A280456.
Sequence in context: A300069 A284586 A281244 * A280456 A103633 A350847
KEYWORD
sign
AUTHOR
Seiichi Manyama, Mar 29 2017
STATUS
approved