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 A144525 #5 Dec 27 2022 14:51:39
%S A144525 1,3,9,63,999,10773,196911,6562701,128858769,1295150391,9472912497,
%T A144525 1895674219911,11402464056957,5518764184829697,207312834548907783,
%U A144525 11211449358195509373,976639971170302762149,590444288071830626391,1001189263964851383868503
%N A144525 Numerators of expansion of exp(1-sqrt(1-3*x)).
%e A144525 1 + (3/2)*x + (9/4)*x^2 + (63/16)*x^3 + (999/128)*x^4 + (10773/640)*x^5 + (196911/5120)*x^6 + ...
%t A144525 CoefficientList[Series[Exp[1-Sqrt[1-3x]],{x,0,20}],x]//Numerator (* _Harvey P. Dale_, Dec 27 2022 *)
%Y A144525 Cf. A144526, A001511, A143991/A143968.
%K A144525 nonn,frac
%O A144525 0,2
%A A144525 _N. J. A. Sloane_, Dec 20 2008