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 A377240 #8 May 03 2025 04:43:54
%S A377240 1,3,0,45,108,1782,8424,94527,596322,5765904,41921874,379715688,
%T A377240 2974945482,26175549087,213735748383,1857916476288,15539695570341,
%U A377240 134524740926700,1141825482025200,9881043227641251,84668712937125633,733670610133591773,6327618171676167195
%N A377240 Expansion of (1 + 9*x/(1 - 9*x)^(1/3))^(1/3).
%F A377240 a(n) = 9^n * Sum_{k=0..n} binomial(1/3,k) * binomial(n-2*k/3-1,n-k).
%F A377240 a(n) ~ 9^n / (Gamma(1/9) * n^(8/9)) * (1 - 2*Gamma(1/9)/(27*Gamma(7/9)*n^(1/3))). - _Vaclav Kotesovec_, May 03 2025
%o A377240 (PARI) a(n) = 9^n*sum(k=0, n, binomial(1/3, k)*binomial(n-2*k/3-1, n-k));
%Y A377240 Cf. A377239.
%K A377240 nonn
%O A377240 0,2
%A A377240 _Seiichi Manyama_, Oct 21 2024