OFFSET
0,3
EXAMPLE
G.f.: A(x) = 1 + x + 4*x^2 + 204*x^3 + 21365*x^4 + 3655450*x^5 + 914720443*x^6 + 314376587287*x^7 + 142230235674161*x^8 + 82054323238595173*x^9 + ...
such that
1 = 1 + ((1+x) - A(x)) + ((1+x)^4 - A(x)^2)^2 + ((1+x)^9 - A(x)^3)^3 + ((1+x)^16 - A(x)^4)^4 + ((1+x)^25 - A(x)^5)^5 + ((1+x)^36 - A(x)^6)^6 + ...
PROG
(PARI) {a(n) = my(A=[1]); for(i=1, n, A=concat(A, 0); A[#A] = Vec( sum(m=0, #A, ((1+x +x*O(x^#A))^(m^2) - Ser(A)^m)^m ) )[#A] ); A[n+1]}
for(n=0, 20, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jun 30 2018
STATUS
approved