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 A370282 #7 Feb 14 2024 10:48:11
%S A370282 1,4,42,499,6250,80634,1060269,14127852,190102482,2577310285,
%T A370282 35150819132,481734467955,6628611532621,91517611501008,
%U A370282 1267182734325900,17589579427715124,244689432718144770,3410399867585709501,47613678409439712861,665756829352248572725
%N A370282 Coefficient of x^n in the expansion of 1/( (1-x)^3 - x )^n.
%F A370282 a(n) = Sum_{k=0..n} binomial(n+k-1,k) * binomial(4*n+2*k-1,n-k).
%F A370282 The g.f. exp( Sum_{k>=1} a(k) * x^k/k ) has integer coefficients and equals (1/x) * Series_Reversion( x * ((1-x)^3 - x) ). See A369215.
%o A370282 (PARI) a(n) = sum(k=0, n, binomial(n+k-1, k)*binomial(4*n+2*k-1, n-k));
%Y A370282 Cf. A069723, A370280.
%Y A370282 Cf. A369215.
%K A370282 nonn
%O A370282 0,2
%A A370282 _Seiichi Manyama_, Feb 13 2024