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 A049391 #9 Jan 16 2020 08:45:44
%S A049391 1,-15,-75,-875,-13125,-223125,-4090625,-78890625,-1577812500,
%T A049391 -32432812500,-681089062500,-14550539062500,-315261679687500,
%U A049391 -6911506054687500,-153040491210937500,-3417904303710937500
%N A049391 Expansion of (1-25*x)^(3/5).
%F A049391 G.f.: (1-25*x)^(3/5).
%F A049391 a(n) = (5^n/n!) * Product_{k=0..n-1} (5*k-3).
%F A049391 a(n) ~ -3/5*Gamma(2/5)^-1*n^(-8/5)*5^(2*n)*{1 + 12/25*n^-1 + ...}. - Joe Keane (jgk(AT)jgk.org), Nov 24 2001
%e A049391 (1-x)^(3/5) = 1 - 3/5*x - 3/25*x^2 - 7/125*x^3 - ...
%t A049391 CoefficientList[Series[(1-25*x)^(3/5), {x, 0, 15}], x] (* _Georg Fischer_, Jan 16 2020 *)
%Y A049391 Cf. A049380.
%K A049391 sign,easy
%O A049391 0,2
%A A049391 Joe Keane (jgk(AT)jgk.org)
%E A049391 Definition corrected by _Georg Fischer_, Jan 16 2020