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 A366070 #11 Sep 29 2023 10:04:21
%S A366070 1,4,23,155,1143,8932,72682,609348,5227035,45659020,404756300,
%T A366070 3632075109,32928392154,301152242600,2775117150576,25741623112539,
%U A366070 240162703635495,2252187478291088,21217451539791085,200709823787548845,1905712342347978340
%N A366070 Expansion of (1/x) * Series_Reversion( x*(1+x-x^2)/(1+x)^5 ).
%F A366070 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/2)} binomial(n+k,k) * binomial(4*n-k+4,n-2*k).
%o A366070 (PARI) a(n) = sum(k=0, n\2, binomial(n+k, k)*binomial(4*n-k+4, n-2*k))/(n+1);
%Y A366070 Cf. A045743, A049125, A279565.
%K A366070 nonn
%O A366070 0,2
%A A366070 _Seiichi Manyama_, Sep 29 2023