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 A366734 #5 Oct 29 2023 22:02:41 %S A366734 1,4,24,236,2504,28332,335656,4108688,51558000,659737684,8575826448, %T A366734 112927383328,1503232394344,20195196226124,273467339844368, %U A366734 3728623506924660,51145851271818536,705322823588365592,9772995790887474920,135992755093954566300,1899633478390401668072 %N A366734 Expansion of g.f. A(x) satisfying 0 = Sum_{n=-oo..+oo} x^n * A(x)^n * (4 - x^(n-1))^(n+1). %C A366734 a(n) = Sum_{k=0..n} A366730(n,k) * 4^k for n >= 0. %F A366734 G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies the following formulas. %F A366734 (1) 0 = Sum_{n=-oo..+oo} x^n * A(x)^n * (4 - x^(n-1))^(n+1). %F A366734 (2) 0 = Sum_{n=-oo..+oo} (-1)^n * x^(n*(n-1)) / ( A(x)^n * (1 - 4*x^(n+1))^(n-1) ). %e A366734 G.f.: A(x) = 1 + 4*x + 24*x^2 + 236*x^3 + 2504*x^4 + 28332*x^5 + 335656*x^6 + 4108688*x^7 + 51558000*x^8 + 659737684*x^9 + 8575826448*x^10 + ... %o A366734 (PARI) {a(n) = my(A=[1]); for(i=1,n, A = concat(A,0); %o A366734 A[#A] = polcoeff( sum(n=-#A,#A, x^n * Ser(A)^n * (4 - x^(n-1))^(n+1) ), #A-2));A[n+1]} %o A366734 for(n=0,30,print1(a(n),", ")) %Y A366734 Cf. A366730, A366731, A366732, A366733, A366735. %K A366734 nonn %O A366734 0,2 %A A366734 _Paul D. Hanna_, Oct 29 2023