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 A259804 #11 Sep 26 2021 08:12:48
%S A259804 1,6,19,68,190,610,1618,4870,12776,37270,97264,277858,723856,2039120,
%T A259804 5309076,14805780,38549984,106693682,277890081,764597138,1992327855,
%U A259804 5456154914,14224333948,38806355844,101220914578,275278038948,718383950316,1948531080114
%N A259804 Guttmann-Torrie series coefficients rho_n*c_{n}^{2} for square lattice, with wedge angle Pi/4.
%C A259804 The sum of square end-to-end distance of all n-step self-avoiding walks on a 2D square lattice confined to one octant of the grid. - _Scott R. Shannon_, Sep 26 2021
%D A259804 A. J. Guttmann and G. M. Torrie, Critical behavior at an edge for the SAW and Ising model, J. Phys. A 17 (1984), 3539-3552.
%Y A259804 Cf. A129700 (number of SAWs in octant grid).
%K A259804 nonn
%O A259804 1,2
%A A259804 _N. J. A. Sloane_, Jul 06 2015
%E A259804 a(23)-a(28) from _Scott R. Shannon_, Sep 26 2021