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 A300048 #22 Aug 06 2023 13:58:17 %S A300048 1,1,2,7,29,131,627,3124,16032,84162,449828,2439550,13391105,74256824, %T A300048 415357737,2340775363,13278009018,75753246286,434392031856, %U A300048 2502289328542,14473290097526,84023214062635,489424396591995,2859551104564120,16754209625090980,98415932763515679,579475837597933632,3419452319373566239,20219028961691299994 %N A300048 G.f. A(x) satisfies A(x)^3 = 1 + x*A(x) + x*A(x)^2 + x*A(x)^6. %C A300048 Compare to: G(x)^3 = 1 + x*G(x) + x*G(x)^2 + x*G(x)^3 holds when G(x) = 1/(1-x). %H A300048 Paul D. Hanna, <a href="/A300048/b300048.txt">Table of n, a(n) for n = 0..300</a> %F A300048 a(n) ~ sqrt(1 + sqrt((9 + 40*sqrt(3))/13)) * (9 + 6*sqrt(3) + sqrt(153 + 100*sqrt(3)))^n / (sqrt(Pi) * n^(3/2) * 2^(n + 3/2) * 3^(n + 3/4)). - _Vaclav Kotesovec_, Aug 11 2021 %F A300048 a(n) = (1/n) * Sum_{k=0..n-1} binomial(n,k) * binomial(n+2*k,n-1-k) for n > 0. - _Seiichi Manyama_, Aug 05 2023 %e A300048 G.f.: A(x) = 1 + x + 2*x^2 + 7*x^3 + 29*x^4 + 131*x^5 + 627*x^6 + 3124*x^7 + 16032*x^8 + 84162*x^9 + 449828*x^10 + 2439550*x^11 + 13391105*x^12 + ... %e A300048 RELATED SERIES. %e A300048 A(x)^2 = 1 + 2*x + 5*x^2 + 18*x^3 + 76*x^4 + 348*x^5 + 1681*x^6 + 8432*x^7 + 43495*x^8 + 229260*x^9 + 1229371*x^10 + ... %e A300048 A(x)^6 = 1 + 6*x + 27*x^2 + 122*x^3 + 579*x^4 + 2862*x^5 + 14588*x^6 + 76146*x^7 + 405039*x^8 + 2187756*x^9 + 11967426*x^10 + ... %e A300048 A(x)^3 = 1 + 3*x + 9*x^2 + 34*x^3 + 147*x^4 + 684*x^5 + 3341*x^6 + 16896*x^7 + 87702*x^8 + 464566*x^9 + 2501178*x^10 + ... %o A300048 (PARI) {a(n) = my(A=1); for(i=1,n, A = (1 + x*A + x*A^2 + x*A^6 +x*O(x^n))^(1/3) ); polcoeff(A,n)} %o A300048 for(n=0,30,print1(a(n),", ")) %Y A300048 Cf. A000108, A106228, A219537. %K A300048 nonn %O A300048 0,3 %A A300048 _Paul D. Hanna_, Feb 25 2018