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 A055406 #14 Mar 31 2025 22:00:28
%S A055406 1,8,106,702,3390,11496,33792,83877,191433,394251,766518,1397065,
%T A055406 2446316,4076126,6601783,10324698,15776495,23436651,34198045,48828417,
%U A055406 68680634,94868383,129404333,173984393,231540046,304058667,395837165
%N A055406 Number of points in N^7 of norm <= n.
%H A055406 Andrew Howroyd, <a href="/A055406/b055406.txt">Table of n, a(n) for n = 0..500</a>
%F A055406 a(n) = [x^(n^2)] (1 + theta_3(x))^7/(128*(1 - x)), where theta_3() is the Jacobi theta function. - _Ilya Gutkovskiy_, Apr 15 2018
%t A055406 a[n_]:=SeriesCoefficient[(1 + EllipticTheta[3, 0, x])^7/(128 (1 - x)), {x, 0, n^2}]; Array[a,27,0] (* _Stefano Spezia_, Mar 31 2025 *)
%Y A055406 Column k=7 of A302998.
%K A055406 nonn
%O A055406 0,2
%A A055406 _David W. Wilson_