This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A358957 #6 Dec 08 2022 07:34:52
%S A358957 1,7,105,1855,36225,753319,16356809,366518975,8412321985,196761671175,
%T A358957 4672976571753,112386313863327,2731613284143345,66992673654966087,
%U A358957 1655756220596437601,41199365822954474670,1031225066096367871764,25947188077245338061147,655925022779049206277461
%N 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).
%C A358957 Related identity: 0 = Sum_{n=-oo..+oo} x^n * (y - x^n)^n, which holds formally for all y.
%F A358957 G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies:
%F A358957 (1) 0 = Sum_{n=-oo..+oo} x^(7*n) * (x^n - 2*A(x))^(8*n+1).
%F A358957 (2) 0 = Sum_{n=-oo..+oo} x^(8*n*(n-1)) / (1 - 2*A(x)*x^n)^(8*n-1).
%e A358957 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 + ...
%o A358957 (PARI) {a(n) = my(A=[1]); for(i=1,n, A=concat(A,0);
%o A358957 A[#A] = polcoeff( sum(n=-#A,#A, x^(7*n) * (x^n - 2*Ser(A))^(8*n+1) ), #A-1)/2);A[n+1]}
%o A358957 for(n=0,25,print1(a(n),", "))
%Y A358957 Cf. A355865, A358952, A358953, A358954, A358955, A358956, A358958, A358959.
%K A358957 nonn
%O A358957 0,2
%A A358957 _Paul D. Hanna_, Dec 07 2022