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 A284317 #14 Mar 27 2017 15:29:04 %S A284317 1,0,0,0,-1,0,0,0,0,-1,0,0,0,1,-1,0,0,0,1,-1,0,0,0,2,-1,0,0,-1,2,-1,0, %T A284317 0,-1,3,-1,0,0,-2,3,-1,0,0,-3,4,-1,0,1,-4,4,-1,0,1,-5,5,-1,0,2,-7,5, %U A284317 -1,0,3,-8,6,-1,0,5,-10,6,-1,-1,6,-12,7,-1,-1,9,-14 %N A284317 Expansion of Product_{k>=0} (1 - x^(5*k+4)) in powers of x. %H A284317 Robert Israel, <a href="/A284317/b284317.txt">Table of n, a(n) for n = 0..10000</a> %F A284317 a(n) = -(1/n)*Sum_{k=1..n} A284103(k)*a(n-k), a(0) = 1. %F A284317 G.f. is the QPochhammer symbol (x^4;x^5)_infinity. - _Robert Israel_, Mar 27 2017 %p A284317 S:= series(mul(1-x^(5*k+4),k=0..200),x,101): %p A284317 seq(coeff(S,x,j),j=0..100); # _Robert Israel_, Mar 27 2017 %t A284317 CoefficientList[Series[Product[1 - x^(5k + 4), {k, 0, 100}], {x, 0, 100}], x] (* _Indranil Ghosh_, Mar 25 2017 *) %o A284317 (PARI) Vec(prod(k=0, 100, 1 - x^(5*k + 4)) + O(x^101)) \\ _Indranil Ghosh_, Mar 25 2017 %Y A284317 Cf. Product_{k>=0} (1 - x^(m*k+m-1)): A081362 (m=2), A284315 (m=3), A284316 (m=4), this sequence (m=5). %Y A284317 Cf. A281243, A284103. %K A284317 sign %O A284317 0,24 %A A284317 _Seiichi Manyama_, Mar 25 2017