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 A284500 #12 Jan 17 2023 12:29:00
%S A284500 1,0,-1,0,0,0,0,0,0,-1,0,1,0,0,0,0,-1,0,1,0,0,0,0,-1,0,2,0,-1,0,0,-1,
%T A284500 0,2,0,-1,0,0,-1,0,3,0,-2,0,0,-1,0,3,0,-3,0,1,-1,0,4,0,-4,0,1,-1,0,4,
%U A284500 0,-5,0,2,-1,0,5,0,-7,0,3,-1,0,5,0,-8,0,5,-1,-1
%N A284500 Expansion of Product_{k>=0} (1 - x^(7*k+2)) in powers of x.
%H A284500 Robert Israel, <a href="/A284500/b284500.txt">Table of n, a(n) for n = 0..10000</a>
%F A284500 a(n) = -(1/n)*Sum_{k=1..n} A284443(k)*a(n-k), a(0) = 1.
%p A284500 S:= series(mul(1-x^(7*k+2),k=0..(100-2)/7),x,101):
%p A284500 seq(coeff(S,x,i),i=0..100); # _Robert Israel_, Jan 17 2023
%t A284500 CoefficientList[Series[Product[1 - x^(7k + 2), {k, 0, 100}], {x, 0, 100}], x] (* _Indranil Ghosh_, Mar 28 2017 *)
%o A284500 (PARI) Vec(prod(k=0, 100, 1 - x^(7*k + 2)) + O(x^101)) \\ _Indranil Ghosh_, Mar 28 2017
%Y A284500 Cf. Product_{k>=0} (1 - x^(7*k+m)): A284499 (m=1), this sequence (m=2), A284501 (m=3), A284502 (m=4), A284503 (m=5), A284504 (m=6).
%Y A284500 Cf. A281458.
%K A284500 sign,look
%O A284500 0,26
%A A284500 _Seiichi Manyama_, Mar 28 2017