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 A371369 #10 Mar 20 2024 09:39:48
%S A371369 1,9,161,3593,89729,2399817,67222433,1946874569,57824172545,
%T A371369 1751650872713,53910484818849,1680961253003401,52987626458710657,
%U A371369 1685806021244435913,54062032254640697505,1745723303156237416265,56713604222408801019905
%N A371369 Expansion of (1/x) * Series_Reversion( x * (1-8*x)^2 / (1-7*x) ).
%H A371369 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A371369 a(n) = (1/(n+1)) * Sum_{k=0..n} 7^(n-k) * binomial(2*n+k+1,k) * binomial(2*n,n-k).
%o A371369 (PARI) my(N=20, x='x+O('x^N)); Vec(serreverse(x*(1-8*x)^2/(1-7*x))/x)
%o A371369 (PARI) a(n) = sum(k=0, n, 7^(n-k)*binomial(2*n+k+1, k)*binomial(2*n, n-k))/(n+1);
%Y A371369 Cf. A082147.
%K A371369 nonn
%O A371369 0,2
%A A371369 _Seiichi Manyama_, Mar 19 2024