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 A286723 #10 Jul 05 2017 02:09:40
%S A286723 1,10,131,2196,45189,1105182,31354119,1012861224,36717532425,
%T A286723 1476342400050,65212709985675,3139386801018300,163605030141437325,
%U A286723 9176588125543758150,551225830134140520975,35305848011347321438800,2401944921672748059294225,172980447467901106243829850
%N A286723 Column k = 1 of the triangle A225471; Sheffer ((1 - 3*x)^(-3/4), (-1/4)*log(1 - 4*x)).
%C A286723 a(n) is, for n >= 1, the total volume of the binomial(n+1, n) rectangular polytopes (hyper-cuboids) built from n orthogonal vectors with lengths of the sides from the set {3 + 4*j | j=0..n}. See the formula a(n) = sigma[4,3]^{(n+1)}_n and an example below.
%F A286723 a(n) = A225471(n+1, 1), n >= 1.
%F A286723 E.g.f.: (d/dx) ((1 - 4*x)^(-3/4)*((-1/4)*log(1 - 4*x))) = (4 - 3*log(1-4*x)) / (4*(1-4*x)^(7/4)).
%F A286723 a(n) = sigma[4,3]^{(n+1)}_n, n >= 0, with the elementary symmetric function sigma[4,3]^{(n+1)}_n of degree n of the n+1 numbers 3, 7, 11, ..., (1 + 4*n), and sigma[4,3]^{(n+1)}_0 := 1.
%e A286723 a(2) = 131 because sigma[4,3]^{(3)}_2 = 3*(7 + 11) + 7*11 = 131. There are three rectangles (2D rectangular polytopes) built from two orthogonal vectors of different lengths from the set of {3,7,11} of total area 131.
%Y A286723 Cf. A008545 (k=0), A225471.
%K A286723 nonn,easy
%O A286723 0,2
%A A286723 _Wolfdieter Lang_, May 29 2017