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 A063026 #16 Sep 26 2023 12:39:42
%S A063026 0,1,1,2,4,9,21,52,135,368,1045,3068,9230,28245,87414,272544,854012,
%T A063026 2685897,8473107,26805994,85045674,270599945,863529480,2763745020,
%U A063026 8870777955,28550721966,92128996782,298004209496,966085311052
%N A063026 Reversion of y - y^2 + y^4 - y^5.
%H A063026 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A063026 a(n+1) = (1/(n+1)) * Sum_{k=0..floor(n/3)} (-1)^k * binomial(n+k,n) * binomial(2*n-3*k,n). - _Seiichi Manyama_, Sep 26 2023
%t A063026 CoefficientList[InverseSeries[Series[y - y^2 + y^4 - y^5, {y, 0, 30}], x], x]
%Y A063026 Cf. A063019.
%K A063026 nonn,easy
%O A063026 0,4
%A A063026 _Olivier Gérard_, Jul 05 2001