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 A284504 #15 Jan 18 2023 02:23:08
%S A284504 1,0,0,0,0,0,-1,0,0,0,0,0,0,-1,0,0,0,0,0,1,-1,0,0,0,0,0,1,-1,0,0,0,0,
%T A284504 0,2,-1,0,0,0,0,-1,2,-1,0,0,0,0,-1,3,-1,0,0,0,0,-2,3,-1,0,0,0,0,-3,4,
%U A284504 -1,0,0,0,1,-4,4,-1,0,0,0,1,-5,5,-1,0,0,0,2,-7,5
%N A284504 Expansion of Product_{k>=0} (1 - x^(7*k+6)) in powers of x.
%H A284504 Seiichi Manyama, <a href="/A284504/b284504.txt">Table of n, a(n) for n = 0..10000</a>
%F A284504 a(n) = -(1/n) * Sum_{k=1..n} A284105(k) * a(n-k), a(0) = 1.
%t A284504 CoefficientList[Series[Product[1 - x^(7k + 6), {k, 0, 100}], {x, 0, 100}], x] (* _Indranil Ghosh_, Mar 28 2017 *)
%o A284504 (PARI) Vec(prod(k=0, 100, 1 - x^(7*k + 6)) + O(x^101)) \\ _Indranil Ghosh_, Mar 28 2017
%Y A284504 Cf. Product_{k>=0} (1 - x^(7*k+m)): A284499 (m=1), A284500 (m=2), A284501 (m=3), A284502 (m=4), A284503 (m=5), this sequence (m=6).
%Y A284504 Cf. A281245.
%K A284504 sign,look
%O A284504 0,34
%A A284504 _Seiichi Manyama_, Mar 28 2017