OFFSET
0,3
FORMULA
EXAMPLE
G.f.: A(x) = 1 + x + 2*x^2 + 4*x^3 + 12*x^4 + 36*x^5 + 112*x^6 + 360*x^7 +...
where
1 - x*A(x) + x^2*A(x)^2 = 1 - x + x^4 - x^9 + x^16 - x^25 + x^36 - x^49 +-...
PROG
(PARI) {a(n)=local(Q=sum(k=1, sqrtint(n+1), (-x)^(k^2))+x^2*O(x^n)); polcoeff( (1-sqrt(1+4*Q))/(2*x), n)}
for(n=0, 30, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 19 2013
STATUS
approved