A358952 a(n) = coefficient of x^n in A(x) such that: 0 = Sum_{n=-oo..+oo} x^(2*n) * (x^n - 2*A(x))^(3*n+1).

1, 2, 18, 124, 1244, 11652, 122153, 1281722, 14009973, 154993908, 1748602308, 19949674928, 230299666100, 2682127476280, 31492460744869, 372295036400060, 4428101312591810, 52949362040059258, 636176332781478365, 7676183282453865394, 92978971123440688904

Offset: 0

Author

Paul D. Hanna, Dec 07 2022

Keywords

• nonn

Comments

Related identity: 0 = Sum_{n=-oo..+oo} x^n * (y - x^n)^n, which holds formally for all y.

Examples

			G.f.: A(x) = 1 + 2*x + 18*x^2 + 124*x^3 + 1244*x^4 + 11652*x^5 + 122153*x^6 + 1281722*x^7 + 14009973*x^8 + 154993908*x^9 + 1748602308*x^10 + ...
		

Links

• Paul D. Hanna, Table of n, a(n) for n = 0..200

Crossrefs

Cf. A355865, A358953, A358954, A358955, A358956, A358957, A358958, A358959.

Programs

PARI

{a(n) = my(A=[1]); for(i=1,n, A=concat(A,0);
A[#A] = polcoeff( sum(n=-#A,#A, x^(2*n) * (x^n - 2*Ser(A))^(3*n+1) ), #A-1)/2);A[n+1]}
for(n=0,20,print1(a(n),", "))

Formula

G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies:

(1) 0 = Sum_{n=-oo..+oo} x^(2*n) * (x^n - 2*A(x))^(3*n+1).

(2) 0 = Sum_{n=-oo..+oo} x^(3*n*(n-1)) / (1 - 2*A(x)*x^n)^(3*n-1).

a(n) ~ c * d^n / n^(3/2), where d = 13.043520100475... and c = 0.432996977380... - Vaclav Kotesovec, Dec 08 2022