OFFSET
0,64
COMMENTS
|a(n)|<2 if n<63, |a(n)|<3 if n<742, |a(n)|<4 if n<8456.
FORMULA
Euler transform of period 6 sequence [ -1, 0, 0, 0, -1, -2, ...].
G.f.: Product_{k>0} (1-x^(6k))^2*(1-x^(6k-1))*(1-x^(6k-5)).
PROG
(PARI) {a(n)=local(A); if(n<0, 0, A=x*O(x^n); polcoeff( eta(x+A)*eta(x^6+A)^3/ eta(x^2+A)/eta(x^3+A), n))}
CROSSREFS
KEYWORD
sign
AUTHOR
Michael Somos, Nov 05 2005
STATUS
approved