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 A055413 #13 Sep 15 2019 13:48:54 %S A055413 1,15,953,12435,88273,394691,1405325,4031123,10248133,23120727, %T A055413 48218513,93417543,172039681,299505299,503363697,813950491,1279144845, %U A055413 1950568311,2912136485,4244109647,6080556217,8545686087,11835454865 %N A055413 Number of points in Z^7 of norm <= n. %H A055413 Andrew Howroyd, <a href="/A055413/b055413.txt">Table of n, a(n) for n = 0..500</a> %F A055413 a(n) = [x^(n^2)] theta_3(x)^7/(1 - x), where theta_3() is the Jacobi theta function. - _Ilya Gutkovskiy_, Apr 14 2018 %Y A055413 Column k=7 of A302997. %K A055413 nonn %O A055413 0,2 %A A055413 _David W. Wilson_