A358957 - OEIS

A358957

a(n) = coefficient of x^n in A(x) such that: 0 = Sum_{n=-oo..+oo} x^(7*n) * (x^n - 2*A(x))^(8*n+1).

1, 7, 105, 1855, 36225, 753319, 16356809, 366518975, 8412321985, 196761671175, 4672976571753, 112386313863327, 2731613284143345, 66992673654966087, 1655756220596437601, 41199365822954474670, 1031225066096367871764, 25947188077245338061147, 655925022779049206277461

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OFFSET

0,2

COMMENTS

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

LINKS

Table of n, a(n) for n=0..18.

FORMULA

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

(1) 0 = Sum_{n=-oo..+oo} x^(7*n) * (x^n - 2*A(x))^(8*n+1).

(2) 0 = Sum_{n=-oo..+oo} x^(8*n*(n-1)) / (1 - 2*A(x)*x^n)^(8*n-1).

EXAMPLE

G.f.: A(x) = 1 + 7*x + 105*x^2 + 1855*x^3 + 36225*x^4 + 753319*x^5 + 16356809*x^6 + 366518975*x^7 + 8412321985*x^8 + 196761671175*x^9 + 4672976571753*x^10 + ...

PROG

(PARI) {a(n) = my(A=[1]); for(i=1, n, A=concat(A, 0);

A[#A] = polcoeff( sum(n=-#A, #A, x^(7*n) * (x^n - 2*Ser(A))^(8*n+1) ), #A-1)/2); A[n+1]}

for(n=0, 25, print1(a(n), ", "))

CROSSREFS

Cf. A355865, A358952, A358953, A358954, A358955, A358956, A358958, A358959.

Sequence in context: A120049 A067420 A368351 * A131869 A132867 A145666

Adjacent sequences: A358954 A358955 A358956 * A358958 A358959 A358960

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Dec 07 2022

STATUS

approved