OFFSET
0,4
LINKS
Paul D. Hanna, Table of n, a(n) for n = 0..300
FORMULA
G.f. A(x) = Sum_{n>=0} a(n)*x^n may be defined by the following.
(1) 1/x = Sum_{n=-oo..+oo} x^n * (A(x) - x^n)^(n-1).
(2) 1/x = Sum_{n=-oo..+oo} (-1)^(n+1) * x^(n^2) / (1 - x^n*A(x))^(n+1).
(3) A(x)/x = Sum_{n=-oo..+oo} x^(2*n) * (A(x) - x^n)^(n-1).
(4) A(x)/x = Sum_{n=-oo..+oo} (-1)^(n+1) * x^(n*(n-1)) / (1 - x^n*A(x))^(n+1).
a(n) ~ c * d^n / n^(3/2), where d = 3.3064656105288278... and c = 0.3845291573508... - Vaclav Kotesovec, Jun 09 2023
EXAMPLE
G.f.: A(x) = 1 + x + 2*x^3 + 3*x^4 + 11*x^5 + 23*x^6 + 76*x^7 + 188*x^8 + 575*x^9 + 1587*x^10 + 4732*x^11 + 13714*x^12 + ...
PROG
(PARI) {a(n) = my(A=[1, 1]); for(i=1, n, A = concat(A, 0);
A[#A] = polcoeff(-1 + x*sum(m=-#A, #A, x^m * (Ser(A) - x^m)^(m-1) ), #A-2); ); A[n+1]}
for(n=0, 30, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jun 09 2023
STATUS
approved