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 A059367 #5 Jan 01 2021 10:09:33
%S A059367 1,2,13,146,2343,48984
%N A059367 From solution to x = tan x (next term is not an integer).
%C A059367 Suppose 1/y = 1/x + arctan(x). Then arctan(x) = Sum_{n>=0} a(n) * y^(2n+1)/(2n+1)!!. Note that a(6) = 6316012/5. a(7) = 38759594. - _Michael Somos_, Jan 01 2021
%D A059367 L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 171, #33.
%Y A059367 Cf. A079330.
%K A059367 nonn
%O A059367 0,2
%A A059367 _N. J. A. Sloane_, Jan 28 2001