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 A360584 #9 Mar 13 2023 04:26:27 %S A360584 1,1,4,29,294,3727,55748,950898,18094313,378363501,8600306451, %T A360584 210773059751,5534376088000,154911828439188,4603267204022882, %U A360584 144710918709587399,4798300212740184379,167370947204751098624,6127130537038980726113,234905895680130694945861,9413383171884998924237972 %N A360584 Expansion of A(x) satisfying [x^n] A(x) / (1 + x*A(x)^(n+2)) = 0 for n > 0. %H A360584 Paul D. Hanna, <a href="/A360584/b360584.txt">Table of n, a(n) for n = 0..300</a> %F A360584 a(n) ~ c * n! * n^(4*LambertW(1) - 1 + 2/(1 + LambertW(1))) / LambertW(1)^n, where c = 0.02048373460253911846... - _Vaclav Kotesovec_, Mar 13 2023 %e A360584 G.f.: A(x) = 1 + x + 4*x^2 + 29*x^3 + 294*x^4 + 3727*x^5 + 55748*x^6 + 950898*x^7 + 18094313*x^8 + 378363501*x^9 + 8600306451*x^10 + ... %e A360584 The table of coefficients in the successive powers of g.f. A(x) begins: %e A360584 n = 1: [1, 1, 4, 29, 294, 3727, 55748, ...]; %e A360584 n = 2: [1, 2, 9, 66, 662, 8274, 122143, ...]; %e A360584 n = 3: [1, 3, 15, 112, 1116, 13776, 200827, ...]; %e A360584 n = 4: [1, 4, 22, 168, 1669, 20384, 293654, ...]; %e A360584 n = 5: [1, 5, 30, 235, 2335, 28266, 402710, ...]; %e A360584 n = 6: [1, 6, 39, 314, 3129, 37608, 530334, ...]; %e A360584 n = 7: [1, 7, 49, 406, 4067, 48615, 679140, ...]; %e A360584 ... %e A360584 The table of coefficients in A(x)/(1 + x*A(x)^(n+2)) begins: %e A360584 n = 1: [1, 0, 1, 13, 166, 2391, 38776, 699060, ...]; %e A360584 n = 2: [1, 0, 0, 7, 119, 1911, 32823, 612983, ...]; %e A360584 n = 3: [1, 0, -1, 0, 64, 1358, 26039, 515774, ...]; %e A360584 n = 4: [1, 0, -2, -8, 0, 724, 18356, 406634, ...]; %e A360584 n = 5: [1, 0, -3, -17, -74, 0, 9702, 284785, ...]; %e A360584 n = 6: [1, 0, -4, -27, -159, -824, 0, 149478, ...]; %e A360584 n = 7: [1, 0, -5, -38, -256, -1759, -10833, 0, ...]; %e A360584 ... %e A360584 in which the diagonal of all zeros illustrates that %e A360584 [x^n] A(x) / (1 + x*A(x)^(n+2)) = 0 for n > 0. %o A360584 (PARI) {a(n) = my(A=[1]); for(i=1,n, A = concat(A,0); %o A360584 A[#A] = -polcoeff( Ser(A)/(1 + x*Ser(A)^(#A+1)), #A-1) );A[n+1]} %o A360584 for(n=0,30,print1(a(n),", ")) %Y A360584 Cf. A360582, A360583. %K A360584 nonn %O A360584 0,3 %A A360584 _Paul D. Hanna_, Mar 12 2023