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 A371520 #11 Mar 27 2024 08:54:00
%S A371520 1,5,40,360,3495,35726,378965,4133080,46059020,522196465,6004261226,
%T A371520 69849651025,820651943130,9723556336780,116056250171385,
%U A371520 1394082307995626,16840510019954835,204453614350921540,2493311080293185200,30528431677508637205,375155454309681439001
%N A371520 G.f. A(x) satisfies A(x) = (1 + x*A(x) / (1-x))^5.
%F A371520 a(n) = 5 * Sum_{k=0..n} binomial(n-1,n-k) * binomial(5*k+4,k)/(4*k+5) = Sum_{k=0..n} binomial(n-1,n-k) * binomial(5*k+5,k)/(k+1).
%F A371520 G.f.: A(x) = B(x)^5 where B(x) is the g.f. of A349332.
%o A371520 (PARI) a(n) = 5*sum(k=0, n, binomial(n-1, n-k)*binomial(5*k+4, k)/(4*k+5));
%Y A371520 Cf. A045868, A371516, A371517, A371521.
%Y A371520 Cf. A349332, A371486.
%K A371520 nonn
%O A371520 0,2
%A A371520 _Seiichi Manyama_, Mar 26 2024