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 A087504 #12 Aug 19 2015 11:59:38
%S A087504 1,1,1,1,2,2,3,3,4,3,4,4,6,5,6,5,7,6,8,7,9,7,9,8,11,9,11,9,12,10,13,
%T A087504 11,14,11,14,12,16,13,16,13,17,14,18,15,19,15,19,16,21,17,21,17,22,18,
%U A087504 23,19,24,19,24,20,26,21,26,21,27,22,28,23,29,23,29,24
%N A087504 Composition length of the n-th symmetric power of the natural representation of a finite subgroup of SL(2,C) of type E_7 (binary octahedral group).
%D A087504 Y. Ito, I. Nakamura, Hilbert schemes and simple singularities, New trends in algebraic geometry (Warwick, 1996), 151-233, Cambridge University Press, 1999.
%H A087504 Harvey P. Dale, <a href="/A087504/b087504.txt">Table of n, a(n) for n = 0..1000</a>
%H A087504 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (1, 0, -1, 2, -1, 0, 1, -1).
%F A087504 G.f.: (1-x^9)/((1-x)(1-x^4)(1-x^6)).
%F A087504 a(0)=1, a(1)=1, a(2)=1, a(3)=1, a(4)=2, a(5)=2, a(6)=3, a(7)=3, a(n)= a(n-1)- a(n-3)+2*a(n-4)-a(n-5)+a(n-7)-a(n-8). [_Harvey P. Dale_, May 09 2012]
%t A087504 CoefficientList[Series[(1-x^9)/((1-x)(1-x^4)(1-x^6)),{x,0,30}],x] (* or *) LinearRecurrence[{1,0,-1,2,-1,0,1,-1},{1,1,1,1,2,2,3,3},31] (* _Harvey P. Dale_, May 09 2012 *)
%o A087504 (PARI) Vec((1-x^9)/((1-x)*(1-x^4)*(1-x^6)) + O(x^80)) \\ _Michel Marcus_, Aug 19 2015
%Y A087504 Cf. A008647.
%K A087504 easy,nonn
%O A087504 0,5
%A A087504 _Paul Boddington_, Oct 23 2003
%E A087504 More terms from _Michel Marcus_, Aug 19 2015