OFFSET
0,5
EXAMPLE
G.f. A(x) = 1 - x + x^3 - 2*x^4 + 2*x^5 - x^6 - x^7 + 4*x^8 - 9*x^9 + ...
G.f. A(x) satisfies A(x) = (1 - x*A(x)) * (1 - x^2*A(x)) * (1 - x^3*A(x)) * ...
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Jan 15 2018
STATUS
approved